Abstract: In an optical pickup device including light sources for emitting laser light, an objective lens for collecting the laser light emitted from the light sources on a disc surface of an optical disc, a light receiving unit for receiving the reflected light reflected by the disc surface, a collimator lens for correcting spherical aberration of the exit light from the objective lens, a lens driving unit for moving the collimator lens in an optical axis direction, and a control unit for controlling the operation of the lens driving unit based on the output of the light receiving unit, the astigmatism of the exit light from the objective lens is corrected by tilting the collimator lens by a predetermined angle by the lens driving unit.

Abstract: An optical pickup includes: a spherical aberration correcting portion for correcting spherical aberration by adjusting a convergence/divergence state of laser light emitted from a light source; a reflecting portion having: a first surface that chooses whether or not to pass laser light emitted from the spherical aberration correcting portion according to the wavelength of the laser light; and a second surface that reflects laser light that has passed through the first surface; and two objective lenses that are selectively used according to whether laser light reflected from the reflecting portion has been reflected by the first surface or by the second surface so as to condense light reflected from the reflecting portion onto a recording layer of an optical disc. Here, between the spherical aberration correcting portion and the objective lenses, there is disposed an astigmatism correcting portion that is formed such that the amount of correction can be changed.

Abstract: An optical pickup includes: a spherical aberration correcting portion for correcting spherical aberration by adjusting a convergence/divergence state of laser light emitted from a light source; a reflecting portion having: a first surface that chooses whether or not to pass laser light emitted from the spherical aberration correcting portion according to the wavelength of the laser light; and a second surface that reflects laser light that has passed through the first surface; and two objective lenses that are selectively used according to whether laser light reflected from the reflecting portion has been reflected by the first surface or by the second surface so as to condense light reflected from the reflecting portion onto a recording layer of an optical disc. Here, between the spherical aberration correcting portion and the objective lenses, there is disposed an astigmatism correcting portion that is formed such that the amount of correction can be changed.

Abstract: A lens holder for an optical pickup comprising: a holding portion for holding an objective lens which concentrates a light beam on a recording surface of an optical recording medium; a protector for preventing the collision between the optical recording medium and the objective lens; a protector placing surface on which the protector is placed. The protector placing surface has on its partial region a protruding portion which protrudes outward, and a part of the protector which is placed on the protector placing surface and formed of a resin sheet protrudes along the protruding portion except the circumferential portion of the protector.

Abstract: An objective lens corresponding to a BD beam light, and an objective lens corresponding to a DVD/CD beam light are arranged parallel to an optical disc. One rising mirror is arranged in a tilted manner on a side opposite to the optical disc of the objective lenses. A first film for reflecting the BD beam light emitted from a laser diode and making the beam light enter the objective lens and transmitting the DVD/CD beam light emitted from a laser diode is arranged on one of the parallel surfaces of a transparent substrate of the rising mirror. A second film for reflecting the DVD/CD beam light transmitted through the first film and the transparent substrate and making the beam light enter the objective lens is arranged on the other surface. An incident optical axis to each objective lens of the BD beam light and the DVD/CD beam light is branched with the rising mirror.

Abstract: An optical disc apparatus includes: a light source unit in which a plurality of light emitting points that emit lights having different wavelengths each other are formed in vicinity; a condenser lens which condenses the light emitted from the light source unit on a recording layer of the optical disc; a photo detecting portion which receives the light reflected by the recording layer of the optical disc, a plurality of photo receiving regions are formed on the photo detecting portion to receive the reflected light in separate positions according to the respective wavelengths which are emitted from the light source unit; and a calculation processing portion, if a first photo receiving region is a photo receiving region which is essentially used to obtain a servo signal at reproduction of an optical disc that has a plurality of recording layers and a second photo receiving region is a photo receiving region not needed to be used essentially to obtain the servo signal among the plurality of photo receiving regio

Abstract: In an optical pickup device including light sources for emitting laser light, an objective lens for collecting the laser light emitted from the light sources on a disc surface of an optical disc, a light receiving unit for receiving the reflected light reflected by the disc surface, a collimator lens for correcting spherical aberration of the exit light from the objective lens, a lens driving unit for moving the collimator lens in an optical axis direction, and a control unit for controlling the operation of the lens driving unit based on the output of the light receiving unit, the astigmatism of the exit light from the objective lens is corrected by tilting the collimator lens by a predetermined angle by the lens driving unit.

Abstract: The present invention provides an optical pickup device in which a liquid crystal device is easily attached, mass productivity is high, a movable actuator is light, excellent response can be obtained and, moreover, the liquid crystal device can be easily controlled. In an optical pickup device in which laser beams emitted from light sources pass through a collimator lens and an objective lens and are condensed to a surface of an optical disc, a liquid crystal device for correcting spherical aberration of an outgoing light from the objective lens is provided in front of the collimator lens when viewed from the light sources. The liquid crystal device has a single electrode formed in a wide range in each of a pair of substrates facing each other while sandwiching liquid crystal.

Abstract: Optical pickup device equipped with liquid crystal diffraction element is provided with liquid crystal diffraction element control portion, which includes detecting portions for detecting light quantities of 0 order light and 1st order light from signal of photo detector for receiving the 0 order light and 1st order light generated by liquid crystal diffraction element, processing portion for determining light quantity ratio of 0 order light to 1st order light from light quantities obtained by detecting portions and for deciding whether or not difference between light quantity ratio and prescribed light quantity ratio is within predetermined range and for determining correction value of voltage to be applied to transparent electrodes if difference is not within predetermined range, and voltage control portion for controlling the voltage value to be applied to transparent electrodes based on process result of processing portion.

Abstract: An optical disc apparatus includes a liquid crystal driver, a laser driver, a storage portion, and a control portion for controlling them, the storage portion stores a correction table of current to be supplied to a laser beam source with a parameter of a voltage to be applied to a liquid crystal element, and the control portion looks up the correction table and determines a correction value of the current for driving the laser beam source in accordance with the voltage to be applied to the liquid crystal element.

Abstract: An optical pickup includes a laser diode for BD, a laser diode for DVD and CD, a collimator lens, an objective lens for BD. A blue color laser beam emitted from the laser diode for BD passes through the collimator lens to become parallel rays, which enter the objective lens for BD. Other red color laser beam and infrared laser beam emitted from the laser diode for DVD and CD pass through the collimator lens to become diverging non-parallel rays, which enter the objective lens for BD. In this way, optical components are arranged.

Abstract: An optical pickup includes a light source, an objective lens for condensing a light beam emitted from the light source on a disk, a hologram element for splitting the light beam reflected by the disk, a photo detector for receiving the split light beam, a holding element for holding the objective lens and the hologram element, and an actuator for driving the holding element, the objective lens and the hologram element as one unit to shift in a tracking direction.

Abstract: A semiconductor laser driving apparatus for directing light to an optical disc for recording a recording mark based on a recording current and reproducing the recording mark to generate a reproduction signal. The apparatus includes a reproduction current generation section; a high frequency current generation section for generating a current including a high frequency component for reducing semiconductor laser noise in the reproduction; a recording current generation section, the recording current including a pulse corresponding to the recording mark and including a plurality of multi-pulses; and a current driving section for amplification. The apparatus further includes a filter to attenuate the enhanced high frequency components in the high frequency current and in the enhanced high frequency component; and a switching section for switching the filter so that the enhanced component in the recording current is superposed on at least one of the multi-pulses.

Abstract: An optical disc drive includes an optical head, a read signal processor, and a controller. The optical head outputs a first read signal representing light reflected from an optical disc and detected at a photodetector. The read signal processor receives the first read signal and outputs the second read signal responsive to a first or second control signal. The second read signal has a predetermined level when output responsive to the first control signal but a level corresponding to that of the first read signal when output responsive to the second control signal. The controller outputs the first and second control signals during first and second periods, respectively. The first period begins before marks are formed on the disc and ends while the marks are formed, and the second period follows the first period. The optical disc drive controls the data write operation in accordance with the second read signal.

Abstract: An optical disk drive reads and/or writes data from/on an optical disk on which a pre-pit has been formed on at least one side edge of a data recording track. The disk drive includes light-emitting element, photodetector section, subtractor and amplifier. The light-emitting element emits a light beam and irradiates the track with the light beam. The photodetector section receives and detects the light beam reflected from the track, thereby generating first and second detection signals, carrying information about shapes of the track at the one and the other side edges thereof, respectively, based on the reflected light beam. The subtractor generates a differential signal representing a difference between the first and second detection signals. The amplifier amplifies the differential signal, output from the subtractor, by a variable amplification factor. The optical disk drive detects the pre-pit in accordance with the amplified differential signal.

Abstract: An optical disk drive reads and/or writes data from/on an optical disk on which a pre-pit has been formed on at least one side edge of a data recording track. The disk drive includes light-emitting element, photodetector section, subtractor and amplifier. The light-emitting element emits a light beam and irradiates the track with the light beam. The photodetector section receives and detects the light beam reflected from the track, thereby generating first and second detection signals, carrying information about shapes of the track at the one and the other side edges thereof, respectively, based on the reflected light beam. The subtractor generates a differential signal representing a difference between the first and second detection signals. The amplifier amplifies the differential signal, output from the subtractor, by a variable amplification factor. The optical disk drive detects the pre-pit in accordance with the amplified differential signal.

Abstract: Address groups are composed of two of address blocks 16, 17, 18, and 19, where the address blocks 16, 17, 18, and 19 are disposed in a sector address region 5 and include identifiable information of address numbers 13 and overlapping sequential numbers 14. The address groups are disposed so that each group is alternately shifted from a track center 2 toward the inner periphery side or the outer periphery side, by a width substantially equal to half the track pitch, along the radius direction.

Abstract: Address groups are composed of two of address blocks 16, 17, 18, and 19, where the address blocks 16, 17, 18, and 19 are disposed in a sector address region 5 and include identifiable information of address numbers 13 and overlapping sequential numbers 14. The address groups are disposed so that each group is alternately shifted from a track center 2 toward the inner periphery side or the outer periphery side, by a width substantially equal to half the track pitch, along the radius direction.

Abstract: Address groups are composed of two of address blocks 16, 17, 18, and 19, where the address blocks 16, 17, 18, and 19 are disposed in a sector address region 5 and include identifiable information of address numbers 13 and overlapping sequential numbers 14. The address groups are disposed so that each group is alternately shifted from a track center 2 toward the inner periphery side or the outer periphery side, by a width substantially equal to half the track pitch, along the radius direction.

Abstract: Address groups are composed of two of address blocks 16, 17, 18, and 19, where the address blocks 16, 17, 18, and 19 are disposed in a sector address region 5 and include identifiable information of address numbers 13 and overlapping sequential numbers 14. The address groups are disposed so that each group is alternately shifted from a track center 2 toward the inner periphery side or the outer periphery side, by a width substantially equal to half the track pitch, along the radius direction.