摘要:
Provided are an optical pick up and an optical component used for the optical pickup which are capable of preventing or restraining occurrence of deviation and unbalance which are caused by assembly errors during manufacturing of optical components, a temperature variation or the like. The optical pickup comprises a laser, a polarization changeover element for changing over a direction of polarization of an optical beam emitted from the laser, a beam splitting element for splitting the laser beam into a plurality of optical paths in accordance with a direction of a polarization, a plurality of objective lenses for focusing laser beams onto a recording layer of the optical disc, a rise-up mirror, and a plurality of coupling lenses arranged respectively intermediate of the plurality of optical paths led to the plurality of objective lenses. The rise-up mirror is arranged intermediate of the plurality of optical paths led to the plurality of objective lenses and adapted to be used common to respective optical beams on the plurality of optical paths. The plurality of the coupling lenses are coupled to and held on one and the same drive portion.
摘要:
Even in an optical disk which includes, within a single disk, plural record areas whose track-pitches differ from each other, a tracking parameter is adjusted in a short time and with a high accuracy. At first, an optical pickup for reading information recorded in the optical disk is displaced into a reference track-pitch area which is one of the plural record areas of the optical disk. Moreover, the tracking gain is adjusted so that the tracking servo gain in this area may exhibit a predetermined characteristic. Also, the value thus acquired is recorded into, e.g., a non-volatile memory. After that, based on the tracking parameter learned/adjusted in the reference track-pitch area, the tracking parameter in another track-pitch area is calculated using the track-pitch ratio therebetween. Thereby it becomes possible to adjust the tracking parameter in a short time and with a high accuracy.
摘要:
A method and an optical disk apparatus that can accurately and stably correct the spherical aberration even for a blank write-once optical disk and can detect a spherical aberration error signal with a simple construction of parts in real time. In a blank write-once disk 20, the tracking servo is switched to an inoperative state, push-pull signals from outputs of the photodetector 12 are detected in a state of “in focus” and in a state of “out focus,” respectively, by a push-pull signal generation circuit 34, and.the amplitudes of these push-pull signals are subjected to difference calculation in a spherical aberration error detector 31 to obtain a spherical aberration error signal A. Then, the spherical aberration is corrected with this spherical aberration error signal A, and subsequently a specific pattern signal is recorded in a trial writing area, this signal is reproduced in the state of “in focus” and in the state of “out focus,” respectively, the amplitude of each reproduced signal is acquired by a reproduced signal generation circuit 32, these amplitudes are subjected to difference calculation in the spherical aberration error detector 31 to obtain a spherical aberration error signal B. The spherical aberration is corrected with this.
摘要:
A high recording-density and highly reliable optical disc according to the two-dimensional PRML system is provided in which periodic signal fluctuations in the readout signal caused by an overall positional displacement of pits between adjacent tracks can be detected at each sampling clock timing and can be tracked and compensated. Two-dimensional inter-symbol interference is compensated during the production and recording of the pattern of the medium. The readout signal is compensated by a process of multi-value tracking before symbols are extracted from the signal.
摘要:
The amplitude deviation of a tracking error signal in an optical disk apparatus is reliably corrected by processing signals at low costs. A servo signal generator generates a tracking error signal and a lens error signal from a photodetected signal. A lens error deviation signal memory circuit stores the lens error signal generated at the servo signal generator, and reproduces the one-turn deviation of the lens error signal. A tracking error signal corrector learns an amplitude correcting value for the tracking error signal from the tracking error signal detected in reproducing the one-turn deviation of the lens error signal, and stores the amplitude correcting value in a correcting signal generator.
摘要:
In an optical disk apparatus, an optical pickup includes an actuator for driving an object lens, and a sensed signal output part for making it possible to generate a tracking error signal and a lens error signal by addition/subtraction, and a signal processor includes a servo signal generator for generating a tracking error signal and a lens error signal on the basis of a signal supplied from the sensed signal output part, and a tracking offset correction quantity signal generator supplied with the lens error signal to output a tracking offset correction quantity signal. DC (direct current) offset correction is conducted by conducting addition/subtraction between the tracking error signal and both the lens error signal and the tracking offset correction quantity signal.
摘要:
An optical disc apparatus which detects an envelope of a tracking error signal in a record or playback mode of an optical disc having recording layers of a multilayer structure, which quantifies a variation caused by multilayer interference (to ΔTES), and which restricts a recording or playback rate when a relationship ΔTES>Vth is satisfied for a predetermined threshold Vth. With such an arrangement, degradation of a recording or reproducing performance or generation of running-off-track resulting from a variation in the tracking error signal caused by stray light reflected by ones of recording layers of the optical disc which are not a recording or reproducing target layer can be suppressed, and a good recording or playback quality can be obtained even in such an optical disc having the plurality of recording layers laminated therein.
摘要:
Provided are an optical pick up and an optical component used for the optical pickup which are capable of preventing or restraining occurrence of deviation and unbalance which are caused by assembly errors during manufacturing of optical components, a temperature variation or the like. The optical pickup comprises a laser, a polarization changeover element for changing over a direction of polarization of an optical beam emitted from the laser, a beam splitting element for splitting the laser beam into a plurality of optical paths in accordance with a direction of a polarization, a plurality of objective lenses for focusing laser beams onto a recording layer of the optical disc, a rise-up mirror, and a plurality of coupling lenses arranged respectively intermediate of the plurality of optical paths led to the plurality of objective lenses. The rise-up mirror is arranged intermediate of the plurality of optical paths led to the plurality of objective lenses and adapted to be used common to respective optical beams on the plurality of optical paths. The plurality of the coupling lenses are coupled to and held on one and the same drive portion.
摘要:
A method and an optical disk apparatus that can accurately and stably correct the spherical aberration even for a blank write-once optical disk and can detect a spherical aberration error signal with a simple construction of parts in real time. In a blank write-once disk 20, the tracking servo is switched to an inoperative state, push-pull signals from outputs of the photodetector 12 are detected in a state of “in focus” and in a state of “out focus,” respectively, by a push-pull signal generation circuit 34, and the amplitudes of these push-pull signals are subjected to difference calculation in a spherical aberration error detector 31 to obtain a spherical aberration error signal A. Then, the spherical aberration is corrected with this spherical aberration error signal A, and subsequently a specific pattern signal is recorded in a trial writing area, this signal is reproduced in the state of “in focus” and in the state of “out focus,” respectively, the amplitude of each reproduced signal is acquired by a reproduced signal generation circuit 32, these amplitudes are subjected to difference calculation in the spherical aberration error detector 31 to obtain a spherical aberration error signal B. The spherical aberration is corrected with this.
摘要:
An absolute accuracy in the range from ±2 nm to ±1 nm for a displacement measurement value is provided by a laser interferometer displacement measuring system. A fluctuating error component that appears corresponding to the wave cycle of laser light is detected and subtracted from the measurement value while a stage is moving, thereby providing a high accuracy.