Patent application number | Description | Published |
20090010119 | Optical Disk Apparatus - An optical disk apparatus according to the present invention includes: a rotation driving section on which an optical disk is to be mounted and which drives the optical disk so as to be rotated; a light source; an objective lens for converging light from the light source onto an optical disk mounted on the rotation driving section; a photodetector having at least two detection sections for detecting reflected light, from the optical disk, of the light; and an error signal generation section for deriving a difference signal and a sum signal of respective outputs from the two detection sections of the photodetector, adjusting an offset in at least the sum signal among the difference signal and the sum signal, and thereafter dividing the difference signal by the sum signal whose offset has been adjusted to generate a position error signal of the objective lens. | 01-08-2009 |
20090154323 | OPTICAL PICKUP DEVICE AND OPTICAL DISC DEVICE - When recording on and/or reproducing from an information recording medium having a plurality of recording layers is performed, there has been a problem in appropriately detecting a control signal at the time of the recording and/or reproducing, since reflected light from a recording layer, which does not undergo the recording and/or reproducing, enters a photodetector concurrently with reflected light from a recording layer which undergoes the recording and/or reproducing. In the present invention, a polarization hologram is used to diffract light outputted from a light source and to generate a main beam, which is a zeroth-order light beam, and a pair of sub beams, which is a positive first-order light beam and a negative first-order light beam each having a polarization direction perpendicular to a polarization direction of the main beam. Accordingly, it is possible to prevent the reflected sub beams from a recording layer, which is a target undergoing recording and/or reproducing, from interfering with the reflected main beam from a recording layer, which is a non-target not undergoing the recording and/or reproducing. Therefore, it is possible to obtain an accurate control signal based on the sub beams, and also possible to realize an optical pickup device having a preferable recording performance. | 06-18-2009 |
20090274022 | OPTICAL DISC DEVICE - A focus error signal is generated by a first-order diffracted light diffracted by regions | 11-05-2009 |
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 |
20110261670 | OPTICAL PICKUP DEVICE AND OPTICAL DISC DEVICE - When recording/reproducing an information recording medium having a plurality of information recording layers, a photodetector receives reflected light from a recording layer which is being recorded/reproduced, as well as reflected light from another recording layer which is not being recorded/reproduced, making it difficult to appropriately detect control signals during a recording/reproducing operation. The present invention employs a polarization hologram element so that the polarization direction of 0 | 10-27-2011 |
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 |
20120257487 | OPTICAL DISC DRIVE - An optical disc drive according to the present invention includes: a laser light source | 10-11-2012 |
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 |
20120320727 | OPTICAL PICKUP AND OPTICAL READ/WRITE APPARATUS - An exemplary optical pickup comprises: a light source with first and second emission points; an optical branching element which branches light emitted from the first emission point into multiple light beams including a first main beam and first sub-beams and which also branches light emitted from the second emission point into multiple light beams including a second main beam and second sub-beams; an optical system which condenses the multiple light beams produced by the optical branching element onto an optical storage medium, thereby making the first and second main beams form a write light beam spot and a read light beam spot, respectively, on a target recording track on the storage medium and making the first and second sub-beams form reference light beam spots and other light beam spots somewhere on the storage medium other than the target recording track. | 12-20-2012 |