Patent application number | Description | Published |
20100232272 | WAVE PLATE, OPTICAL PICKUP AND OPTICAL DISC APPARATUS - An optical pickup includes a wave plate on an optical path to be followed by every light beam emitted from three light sources (with wavelengths λ | 09-16-2010 |
20110002216 | OPTICAL PICKUP DEVICE AND OPTICAL DISC DEVICE - Regarding optical pickup devices usable for performing recording on and reproduction from a plurality of types of optical discs, there is a problem that because of the structure of locating many optical elements in a height direction of an optical system, the height of the optical system is increased and so it is difficult to realize a thin and compact optical pickup device. According to the present invention, a first wave plate is located between a first light source and a first mirror, a second wave plate is located between a second light source and a second mirror, and the first wave plate and the second wave plate cause a desirable phase shift to light beams of the first through third wavelengths. Owing to this, the number of optical elements located in the height direction of the optical system can be decreased, and so the height of the optical system can be reduced. | 01-06-2011 |
20110276989 | OPTICAL PICKUP DEVICE AND OPTICAL DISC DRIVE - Has an object of providing an optical pickup capable of realizing tracking control or focus control at a higher level of precision even when relative positions of a light source and a light detector are shifted due to a change in the environmental temperature, long-term deterioration or the like. The optical pickup includes a base member; a light source, fixed to the base member, for emitting a laser beam; an objective lens for collecting the laser beam onto an optical disc; a light detector, fixed to the base member, for detecting the laser beam reflected by the optical disc; fixing means for fixing the light source and/or the light detector to the base member; and a light blocking section for blocking a central portion of the laser beam in a circular shape on an optical path between the collimator lens and the light detector. | 11-10-2011 |
20120117580 | OPTICAL PICKUP AND OPTICAL DISC DRIVE INCLUDING THE OPTICAL PICKUP - According to the present invention, a tracking error signal can be obtained with good stability by the three-beam differential push-pull method even if the track guide groove direction of the optical disc changes as viewed from the objective lens. | 05-10-2012 |
20120287766 | OPTICAL PICKUP DEVICE AND OPTICAL DISC DEVICE - When performing recording/reproduction of information for a given recording layer of an optical disc having three recording layers, influences of reflected light from other recording layers are reduced or removed, thus making it possible to obtain a more stable RF signal or focus error signal. | 11-15-2012 |
20130077456 | OPTICAL PICKUP AND OPTICAL READ/WRITE APPARATUS - In one embodiment, an optical pickup includes an optical system which forms multiple light beams based on the light emitted from a light source and which converges a write beam and a read beam, thereby forming a main spot and a sub-spot, respectively, on an optical storage medium. This optical system converges the write and read beams onto the optical storage medium so that the main spot moves through the same region on the optical storage medium ahead of the sub-spot. The optical pickup further includes a detector for sensing the write and read beams reflected from the storage medium. The detector includes a first photodiode | 03-28-2013 |
20130094338 | OPTICAL PICKUP AND OPTICAL READ/WRITE APPARATUS - An optical pickup includes: a light source; a first diffractive element which diffracts light polarized in a particular direction; an objective lens; a lens actuator which shifts the objective lens so that the magnitude of shift from its initial position in a tracking direction has an upper limit of 0.3 mm to 0.6 mm; a wave plate; a second diffractive element which has two diffraction regions configured to diffract light polarized in a direction that intersects with the particular direction at right angles and which splits the write beam reflected from the optical storage medium through each diffraction region into a transmitted light beam and at least one diffracted light beam; and a photodetector which detects the transmitted light beam, the diffracted light beams that have left the two diffraction regions, and the read beam reflected from the optical storage medium. | 04-18-2013 |