摘要:
An optical disc apparatus includes: a converging section for converging a light beam and irradiating a rotating information medium with the converged light beam; a moving section for moving the converging section, thereby moving a converging point of the converged light beam in a direction perpendicular to an information surface of the information medium; a converging state detection section for generating a focus servo signal which represents a converging state of the light beam on the information medium based on reflected light or transmitted light of the light beam from the information medium; a focus servo control section for controlling the moving section based on the focus servo signal, so that the light beam reaches a predetermined converging state on the information medium; and a focus pull-in section for turning ON the control by the focus servo control section, wherein the focus pull-in section turns ON the control by the focus servo control section in a case where the focus pull-in section determines that the converging point of the light beam is located in the vicinity of the minimum velocity position on the information medium axial deviation.
摘要:
An optical disc drive includes a light source, a lens, a focusing section, a spherical aberration corrector, a focus signal generator, a gain calculator and a processor. The focusing section forms a beam spot in a focusing state on the information storage layer of an optical disc by controlling the position of the lens. The spherical aberration corrector changes a spherical aberration with the beam spot in a focusing state according to a drive value of a driving signal supplied to the spherical aberration corrector. The focus signal generator generates a focus signal representing the focusing state of the beam spot. The gain calculator calculates a loop gain of a focus control system in response to the focus signal. The processor determines the drive value for the spherical aberration corrector by the loop gain.
摘要:
An optical disc drive is used to read and/or write data from/on an optical disc having a data storage layer. The drive corrects electrical offset while reading and/or writing data. The drive updates a correction value based on an electrical offset detected at correcting operation or a value derived using electrical offset values that has been detected and stored, without detecting an electrical offset at correcting operation. Therefore, the optical disc drive can correct the electrical offset less often.
摘要:
Provided is an optical disc device including a focus control unit for performing control so that a convergent point of a main beam converges on a predetermined information layer, a tracking control unit for performing control so that the convergent point of the main beam scans a predetermined track or a predetermined mark sequence on an information layer, a sub beam receiving unit for receiving a sub beam reflected off the information layer and outputting a signal according to an amount of beam received, and a microcomputer for detecting, during a recording operation of recording the information, a focus loss-of-control state where the convergent point of the main beam deviates from the predetermined information layer or a tracking loss-of-control state where the convergent point of the main beam deviates from the predetermined track or the predetermined mark sequence on the information layer.
摘要:
With a large capacity of an optical disk and high-speed recording, a frequency of a recording signal is increased and a pulse width is narrowed. In the case that a laser is driven by a signal having the short pulse width, unfortunately the high-speed recording is hardly performed to an optical disk when a rise time and a fall time of the optical pulse are lengthened.During user data recording, a bottom driving current is set to a second bottom driving current value that is a current value of a threshold or less, so that the rise time and the fall time of the optical pulse can be shortened to perform the high-speed recording of the optical disk.
摘要:
An optical disk apparatus of the present invention measures a surface deflection component (shape of surface deflection) from a low-pass component of a compensating filter in a surface deflection measuring part provided in a DSP. Furthermore, the optical disk apparatus calculates timing at which a positional change in a surface deflection component in time required for focus jumping is a predetermined value or less in a timing calculating part, and starts focus jumping at the timing. Because of this, stable focus jumping is made possible.
摘要:
An optical disc apparatus includes: a converging section for converging a light beam and irradiating a rotating information medium with the converged light beam; a moving section for moving the converging section, thereby moving a converging point of the converged light beam in a direction perpendicular to an information surface of the information medium; a converging state detection section for generating a focus servo signal which represents a converging state of the light beam on the information medium based on reflected light or transmitted light of the light beam from the information medium; a focus servo control section for controlling the moving section based on the focus servo signal, so that the light beam reaches a predetermined converging state on the information medium; and a focus pull-in section for turning ON the control by the focus servo control section, wherein the focus pull-in section turns ON the control by the focus servo control section in a case where the focus pull-in section determines that the converging point of the light beam is located in the vicinity of the minimum velocity position on the information medium axial deviation.
摘要:
Provided is an optical disk apparatus capable achieving stable focus control or tracking control. A first detector receives reflected light from an object lens optical system, a second detector receives reflected light from a prescribed information layer, a positional deviation determination unit determines positional deviation between a focal point of a light beam and a point where information on the prescribed information layer is recorded or reproduced, on the basis of a signal from the second detector, a stray light determination unit determines a surface stray light component which is reflected light from the surface of an optical disk and is included in the signal from the positional deviation determination unit, on the basis of the signal from the first detector, and a stray light correction unit corrects the signal output from the positional deviation determination unit on the basis of the surface stray light component thus determined.
摘要:
An optical head (10) focuses and irradiates a servo light beam onto at least one servo layer, and focuses and irradiates a recording/reproducing light beam onto a plurality of recording layers. An initial recording unit (20) records layer position information for specifying a position of each recording layer in advance in a predetermined position of each recording layer before recording user data in use of the recording/reproducing light beam, a layer position detection unit (21) reads layer position information in a predetermined recording layer by using the recording/reproducing light beam, and detects which one of the plurality of recording layers is the predetermined recording layer where the focal point of the recording/reproducing light beam is positioned, based on the read layer position information, and a seeking unit (22) moves the focal point of the recording/reproducing light beam to a target position based on the detected layer position.
摘要:
Provided is an optical disk apparatus capable achieving stable focus control or tracking control. A first detector receives reflected light from an object lens optical system, a second detector receives reflected light from a prescribed information layer, a positional deviation determination unit determines positional deviation between a focal point of a light beam and a point where information on the prescribed information layer is recorded or reproduced, on the basis of a signal from the second detector, a stray light determination unit determines a surface stray light component which is reflected light from the surface of an optical disk and is included in the signal from the positional deviation determination unit, on the basis of the signal from the first detector, and a stray light correction unit corrects the signal output from the positional deviation determination unit on the basis of the surface stray light component thus determined.