Abstract: An optical disk apparatus includes a rotary driving unit rotating an optical disk which is flexible, an optical pickup irradiating light upon a recording surface of the optical disk on which writing/reading of information is performed, a stabilizing unit stabilizing vibration of the optical disk in a rotary axial direction by using pressure difference of air flow at least on a portion where writing/reading is performed, and being disposed on a side of the optical disk opposite to a side on which the recording surface is provided, and a control-adjustment unit analyzing a value of a tracking error signal of the optical disk obtained by scanning along a groove of the optical disk with use of the optical pickup, comparing the analyzed value of the tracking error signal of the optical disk and a value priorly obtained by scanning along a groove of a standard disk prepared beforehand, and adjusting a positional relation between the optical disk and the stabilizing member in a three dimensional space according to t

Abstract: An optical disc device includes a laser diode which irradiates an optical disc having a plurality of layers with laser light, a photodetection section which detects laser light reflected by the optical disc, which comprising a pair of sub-photodetectors and a main photodetector provided between the pair of sub-photodetectors, a focus error signal generation circuit which generates a focus error signal from a photodetection signal output by the main photodetector, a tracking error generation circuit which generates a tracking error signal from the photodetection signal output by the main photodetector and a photodetection signal output by the pair of sub-photodetectors, and a layer determination signal processing circuit which generates a layer determination signal from the photodetection signal output by the pair of sub-photodetectors and determines in which of the layers a focus of the laser light is located, on the basis of the layer determination signal and focus error signal.

Abstract: A device includes: an objective lens that serves as a lens having a first numerical aperture when a first optical beam corresponding to a first optical disc converges on the first optical disc while serving as a lens having a second numerical aperture when a second optical beam corresponding to a second optical disc converges on the second optical disc; a section that generates a reflection optical signal from the first or second optical beam reflected by the first or second optical disc; and a section that determines whether an unknown disc is the first optical disc based on a degree of matching between the waveform of the reflection optical signal obtained when the first optical beam is emitted to the first optical disc, and the waveform of the reflection optical signal obtained when the first optical beam is emitted to the unknown disc.

Abstract: An optical disk apparatus includes a light focusing element arranged to face a disk and to focus light emitted from a light source on the disk, an actuator to move the light focusing element towards and away from the disk according to an actuator driving voltage, a light intensity detection unit to detect an intensity of light reflected by the light focusing element and generate a gap error signal based on the detected intensity, a servo unit to generate the actuator driving voltage and a predetermined threshold voltage based on the gap error signal generated by the light intensity detection unit and to provide the actuator driving voltage to the actuator, a distance detection unit to detect a first distance at which the actuator driving voltage is maintained when the threshold voltage is detected using the gap error signal and to detect a second distance at which a gap between the light focusing element and the disk is shorter than the first distance and at which a gap servo operation is started based on the

Abstract: A method of determining a disk type of an optical disk is provided to comprise steps of: using a first light path for forming an incident beam; moving an objective lens system corresponding to the first light path from a start position towards the optical disk; receiving a sensor output signal during the movement of the objective lens system, wherein the sensor output signal includes a central aperture signal; determining the disk type of the optical disk according to the central aperture signal.

Abstract: A track-crossing signal generator includes a bottom envelope detecting unit, a defect detector, an auto gain control unit, and an amplifier. The bottom envelope detecting unit receives a radio frequency signal, and outputs a bottom envelope signal. The defect detector is electrically connected to the bottom envelope detecting unit for receiving the bottom envelope signal and generating a defect signal when a defect area is formed on a disc track. The auto gain control unit is electrically connected to the bottom envelope detecting unit for receiving the bottom envelope signal and dynamically adjusting a gain value according to the amplitude of the bottom envelope signal. The amplifier is electrically connected to the bottom envelope detecting unit and the auto gain control unit for receiving the bottom envelope signal and dynamically adjusting the bottom envelope signal according to the gain value, thereby amplifying the bottom envelope signal as a track-crossing signal.

Abstract: A phase error detection apparatus capable of performing offset correction of a tracking error signal accurately even when there is a defect or a non-recorded position on an optical disc. There are provided a phase difference detection circuit (107) which receives two sequences of digital signals, performs phase comparison using a distance between zerocross points of the two sequences of digital signals, and outputs a phase comparison result PCR and a phase comparison completion signal PCC, and an offset control circuit (11) which outputs an offset correction amount for each phase comparison completion signal PCC from the phase difference detection circuit (107), and the offset correction amount ?? is added to the phase comparison result PCR to avoid offset correction in a position where phase comparison is not carried out.

Abstract: Amplitude and frequency of a high-frequency signal superposed on a reproduction laser beam are changed in accordance with a reproduction spot diameter on the surface of the recording layer upon discrimination of an optical disk in initial adjustment after insertion of the optical disk and change of a layer of a multi-layer optical disk. Further, the high-frequency signal is not superposed on the reproduction laser beam until end of the discrimination and change to a target layer upon discrimination of the optical disk and change of a layer of a multi-layer optical disk.

Abstract: A method for detecting whether vertical deviation of an optical disc occurs is provided. First, before a pickup head is successfully focused on the optical disc, a pickup head is actuated based on an input control signal so as to generate a focus error signal with a plurality of S-curves. Then, a plurality of zero crossing points of the S-curves in the focus error signal is identified and a plurality of input control values respectively corresponding to the zero crossing points is obtained. A variation of the input control values is then calculated. Whether vertical deviation of the optical disc occurs can be determined according to the variation of the input control values.

Abstract: A method for reducing overall power calibration time and increasing the number of power calibrations that can be done on an optical record carrier includes performing a first set of power calibration procedures on an optical record carrier at a first recording speed in a first set of calibration areas, and performing a further set of power calibration procedures on the optical record carrier at a recording speed different from the first recording speed. The further set of power calibration procedures partly uses information from the first set of calibration areas.

Abstract: An apparatus for detecting a tracking error signal includes an optical detector to receive light beams reflected from an optical disc and having a plurality of detecting regions; and a phase difference extracting unit to extract a phase difference between a pair of optical signals output from the optical detector, wherein the phase difference extracting unit repeatedly moves a first graph representing one optical signal from among the pair of optical signals by a predetermined distance with respect to a second graph representing another optical signal from among the pair of optical signals, the first and second graph represent optical signal values with respect to t-axis, adds differences between optical signal values of the first graph and optical signal values of the second graph corresponding to predetermined positions of the t-axis, the adding differences is repeated for each of the repeatedly moved positions of the first graph, and outputs a moved distance of a position where the added value is smallest

Abstract: A recording and reproducing apparatus includes: an optical head unit irradiating a laser beam on an optical recording medium and performing writing and readout of information represented by marks and spaces on the medium; a laser-driving-pulse generating unit generating and supplying a laser driving pulse to the head unit, and causing the head unit to execute laser beam irradiation; an evaluation-value measuring unit measuring an evaluation value representing an error of an edge position of the mark; and a control and calculating unit causing the apparatus to separately execute, concerning mark lengths to be adjusted among mark lengths of the laser driving pulse, for each set of mark lengths grouped in advance, trial writing with shift amounts of edge positions of a laser driving pulse concerning the lengths belonging to the set changed, causing the apparatus to execute readout of a signal recorded by the execution of the trial writing, causing the measuring unit to measure an evaluation value under setting o

Abstract: A method and apparatus for controlling a focus servo of an optical disk drive is provided. The focus servo controlling method includes the operations of, when an operating mode enters into a focus pull-in mode, detecting a period of time that satisfies a first threshold condition, the first threshold condition set to determine a duration in which a focal point of an optical signal emitted from a pickup is passing through a cover layer of a disk, the determination made by using a first signal proportional to a detected portion of an optical signal reflected by the disk, and preventing focus servo control from being performed during a detected period of time that first satisfies the first threshold condition since the operating mode entered into the focus pull-in mode.

Abstract: A lens position control method is disclosed. Either an objective lens or a master disc having a resist material film on its substrate is moved, thereby changing a distance between the objective lens and the master disc surface. A return laser beam transmitted through the objective lens and reflected by the master disc surface is detected by a photodetector. The movement of either of them is stopped when the master disc is located near a focal point of the objective lens and the return laser beam is detected. Limit data is rewritten to data corresponding to a position obtained by adding a movement permission amount smaller than a working distance of the objective lens to the stop position. When the return laser beam is not detected, the movement which changes the distance between them is stopped at a position corresponding to the limit data.

Abstract: In a multilayer disc has an increased number of recording layers) spaced by spacing from each other, a generation interval between focus error (FE) signals detected from the respective recording layers becomes small. This causes mutual interference between the FE signals and a resulting undesired offset and the like in the signals, leading to a significantly deteriorated quality of the FE signals. To avoid this, in an optical pickup device according to the present invention, detection surfaces are newly added at positions adjacent to the FE signal detection surfaces, a predetermined detection signal obtained from the newly-added detection surfaces is multiplied by a predetermined coefficient value depending on the spacing between the recording layers, and the multiplied signal is subtracted from the original FE signal. As a result, mutual interference between the FE signals can be remarkably reduced.

Abstract: An optical disc apparatus according to the present invention steadily performs a focus jump operation and a track-crossing seek operation relative to an optical disc having a plurality of recording layers. A signal processing section generates a focus error signal based on a conventional astigmatism detection (CAD) system and a focus error signal based on a differential astigmatism detection (DAD) system from a detection signal generated by an optical detector. When a focus jump is to be performed from one recording layer of the optical disc to another recording layer, a focus drive signal that is generated from the focus error signal based on the CAD system is used. When a read/write operation is to be performed in relation to one recording layer, a focus drive signal that is generated from the focus error signal based on the DAD system is used.

Abstract: An information recording and reproducing apparatus records data on and reproduces data from each of a plurality of recording layers of a recording medium. A controller (7) controls a formatting process to format the recording medium (1) by performing a first formatting process on the data area of a recording layer. The first formatting process comprises formatting the data area in a series of recording increments that progress from the inner side of the data area to the outer side of the data area. Within each recording increment the formatting is performed along a path extending from the outer side of the data area to the inner side of the data area. A second formatting process on the data area of another recording layer once the first formatting process has been completed, the second formatting process being performed along a path extending from the inner side of the data area of the other recording layer to the outer side of the data area of the other recording layer.

Abstract: A method and an apparatus for deciding a spherical aberration compensation (SAC) value for an optical storage medium are provided. The optical storage medium comprises at least one recording layer and a cover layer. The SAC value is suitable for a selected one of the at least one recording layer. First, a focus search on the optical storage medium is performed to derive a focus error (FE) signal in response to a testing SAC value. Then, a center level and a center basis corresponding to the testing SAC value according to the FE signal is determined. The SAC value according to the center level, the center basis, and the testing SAC value is also determined. When the center level and the center basis are equal, the SAC value is determined to be the testing SAC value.

Abstract: An optical drive includes: an optical pickup; a preprocessing circuit which processes an optical signal detected by the optical pickup; nonvolatile memory having stored therein relation information which represents the relation of a signal balance with respect to a signal difference between a TE signal and an FE signal at the time of a predetermined operation of the optical pickup; and a central processing circuit which performs focus control of the optical pickup. The preprocessing circuit generates the signal balance of the optical pickup. The preprocessing circuit also obtains the FE signal and the TE signal with respect to the optical disc. The central processing circuit derives a phase difference and an amplitude difference from the signal balance and the relation information, and calculates, based on the differences and the TE signal, a FE signal suitable for the predetermined operation.

Abstract: A highly reliable optical disk apparatus adapted to record and reproduce the information in and from plural types of optical disks is disclosed. An acquisition unit acquires a predetermined signal from the reflected light obtained by radiating a predetermined laser on each of the optical disks. A comparator compares the waveform of the signal acquired by the acquisition unit with the comparative waveform of the signal stored in a memory beforehand and obtained from the radiated laser corresponding to the optical disk. An identification unit identifies the type of the optical disk based on the result of comparison by the comparator.

Abstract: An optical disc apparatus includes an emitter which emits a laser beam to a optical disc, a divided photodetector including a first dived portion and a second dived portion disposed in a light path of the reflected beam from the optical disc, and producing a first photodetector signal and a second photodetector signal, a phase difference detector which produces a phase difference signal from a phase difference between the first and the second photodetector signals, an integrator which produces a integral signal from a integration of the phase difference signal, a tracking controller configure to perform tracking control based on the integral signal, and a limiter which limits a signal to be supplied from the divided photodetector to the phase difference detector or a signal to be supplied from the phase difference detector to the integrator based on a detection status of a signal detected by the dived photodetector.

Abstract: A recording and reproducing area and a reproduction-only area are formed by wobbling a groove formed in a spiral fashion to form a track to be tracked on a disk. The recording and reproducing area has address information recorded by wobbling of the groove and information recorded and reproduced by phase change marks on the track formed by the groove where the address information is recorded. The reproduction-only area has prerecorded information recorded by wobbling of the groove.

Abstract: A pickup apparatus including: at least a coil constituting an actuator, a signal to be sent to the coil being obtained by calculation using an algorithm on the basis of at least one of a focus error signal and a tracking error signal.

Abstract: An optical disc apparatus capable of discriminating swiftly and accurately a dual disc from other discs and an optical disc discriminating method, wherein the optical disc apparatus irradiates laser beams having a different wavelength onto the optical disc, detects the reflected light obtained by the irradiation of the laser beams having the individual wavelengths, determines amplitude of an error signal according to the detected results of the individual reflected lights, and discriminates the optical disc based on a ratio of amplitudes of the individual reflected lights.

Abstract: A disc discriminating method for use in an optical disc drive includes the following steps. Firstly, an optical pickup head of the optical disc drive is controlled to move in a first direction when the optical pickup head is in a track-unlocked state. Then, a tracking error signal and a radio frequency signal are generated. According to the tracking error signal, a tracking error zero crossing signal is obtained. According to the radio frequency signal, a radio frequency zero crossing signal is obtained. According to a phase relation between the tracking error zero crossing signal and the radio frequency zero crossing signal, the disc is discriminated as an on-groove recording disc or an in-groove recording disc.

Abstract: A method for detecting a media type of an optical disc system comprising the steps of (A) checking for a first wobble signal associated with a first media type, (B) if step (A) detects the first wobble signal, operating the optical disc system as the first media type, (C) checking for a second wobble signal associated with a second media type, and (D) if step (C) detects the second wobble signal, operating the optical disc system as the second media type.

Abstract: An optical disk device includes a DPDTE signal generating section that detects misalignment between a light spot and a mark or a pit, an FE signal generating section, an optical crosstalk correcting section which corrects a signal output by the FE signal generating section using the DPDTE signal generating section, and a focus control section which controls an actuator so that a light beam converges on an information layer. The DPDTE signal generating section detects the misalignment on the basis of phase information obtained from signals received from predetermined light receiving areas. The optical crosstalk correcting section performs a correcting operation of removing a signal component from predetermined receiving areas of a detector which component is used for a DPDTE signal, the signal component being contained in the signals from the predetermined light receiving areas of the detector which signals are used by the FE signal generating section.

Abstract: Detection is made as to at least one of a ratio between a tracking error and a focus error, and a duty cycle of an off-track signal with respect to an optical disc. A decision is made as to whether or not the optical disc is playable on the basis of the detected at least one of the ratio and the duty cycle. The ratio is a ratio of the focus error to the tracking error or a ratio of the tracking error to the focus error.

Abstract: An optimum method for adjusting the physical position or angle of an optical pickup (a1) is automatically selected for each optical disc signal processing device so that a control target value after adjusted is included in a previous margin measurement result which is stored in a nonvolatile memory, thereby providing an optical disc signal processing device, an optical disc signal processing method, an optical disc reproduction and recording device, and an optical disc reproduction and recording method, which can reduce the start-up time and the recording start time, and enhance the user's convenience.

Abstract: An optical disc drive according to the present invention is designed to read data from a multilayer optical disc 100, from/on which data can be read or written using a light beam. The drive includes a light source 222 for emitting a light beam, an objective lens 230 for converging the light beam, a photodetector 236 for detecting the light beam that has been reflected from the disc, and a control section 246 for setting a read power for a particular one of the multiple storage layers of the disc by reference to a read power table 501b. The table 501b stores multiple read powers for the respective storage layers in order to make S-curves of a focus error signal obtained from the respective layers have predetermined amplitudes. In this manner, the optical disc drive of the present invention can be loaded with a multilayer optical disc more smoothly by setting the best read powers for the respective storage layers of the disc.

Abstract: When first-order diffracted beams leak into a region, which is for receiving only a zeroth-order diffracted beam from an optical disc, due to positional displacement between an objective lens and a hologram element, an offset compensation signal includes an AC component, the offset compensation signal preferably including a DC component only. Accordingly, there may be caused deterioration in a modulation degree of the tracking error (TE) signal. A partial light shielding element 110 is formed on a hologram surface 112a along boundaries between a light receiving region (121a), which receives a zeroth-order diffracted beam, and light receiving regions (121b, 121c), which receive the zeroth-order diffracted beam and first-order diffracted beams, so as to cover the light receiving region (121a). Further, the partial light shielding element 110 shifts phases of transmitted light beams by ?, whereby the TE signal is offset-compensated, and the modulation degree can be improved.

Abstract: An optical disc device includes a control part for causing processing of determining a type of an optical disc to be executed. The processing caused by the control part to be executed for determining the optical disc includes: signal acquisition processing of acquiring a pull-in signal (sum signal of reflected signal) and an RF signal (reproduced signal) by moving an objective lens in either of a direction approaching the optical disc and a direction separating from the optical disc; and determination processing of deciding whether or not to correct the pull-in signal acquired in the signal acquisition processing and determining the type of the optical disc by using either of amplitude of the acquired pull-in signal and a correction value with which the amplitude of the acquired pull-in signal is corrected by using a predetermined value obtained from the acquired RF signal.

Abstract: A method for controlling focus on a label side of a light-scribe disc divides the label side into several zones, finds the maximum SBAD and the corresponding focus volt and spoke during focusing on each zone, approaches a primary focus volt level curve, compensates a predetermined volt to focus on the label side, checks the maximum SBAD and the corresponding focus volt and spoke between the primary focus volt level curve and the compensation volt on each zone, and approaches a calibrating focus volt level curve to reduce errors.

Abstract: [PROBLEMS] To perform highly accurate focus control in an optical recording medium of multilayer structure having an interface of each layer with a reflectance reduced as much as possible. [SOLVING ELEMENT] In a focus control apparatus with optical pickup for use in an optical recording medium of multilayer structure, laser light irradiating device including a laser light source (50) and an objective lens (54) irradiates laser light to an optical recording medium (D), a photodetector (55) detects an optical characteristic change associated with multiphoton absorption caused when the laser light is condensed to at least one of recording layers, and in accordance with the detection result, focus control in the optical pickup is performed for an arbitrary recording layer (L1 to Ln).

Abstract: A gap pull-in method and an optical disc apparatus. Whether light condensed on a disc as an actuator ascends is near-field light is determined using a gap error signal. The range of an actuator driving voltage value during a section where the decrease rate of the gap error signal is constant is obtained when it is determined that the light condensed on the disc is near-field light. Gap pull-in is performed on the disc during a section where the actuator driving voltage value is within the obtained range.

Abstract: An optical disc apparatus that records recording marks in a plurality of mark layers by irradiating predetermined light onto a disc-like volume type recording medium on the basis of information to be recorded is disclosed. The apparatus includes: a first focus position adjusting means for adjusting the position of a focus on which a first light beam focuses within the volume type recording medium, in the direction of an optical axis of the first light beam; a second focus position adjusting means for adjusting the position of a focus on which a second light beam focuses within the volume type recording medium, in the direction of an optical axis of the second light beam; a focus control means for controlling the first focus position adjusting means and the second focus position adjusting means; and a recording control means for forming the recording marks at the positions of respective focuses.

Abstract: An optical disk device includes an optical pickup, a focus drive section, a detection section, a time measurement section and a disk identification section. The detection section detects reflected light reflected from an optical disk while the focus drive section moves a focus position of the optical pickup. The time measurement section measures a focus search time between when the reflected light reflected from a disk surface of the optical disk is detected and when the reflected light reflected from an information recording layer of the optical disk is detected. The time measurement section measures a false reflection search time between when the reflected light reflected from the disk surface is detected and when false reflection light is detected. The disk identification section calculates a ratio of the focus search time to the false reflection search time, and identifies a type of the optical disk based on the ratio.

Abstract: An optical disc apparatus and a focus position control method can highly accurately record recording marks representing information on or reproduce such recording marks from an optical disc. A blue light beam is irradiated onto the target depth to be irradiated by driving an objective lens to focus a red light beam in a reflection/transmission film formed in the optical disc and displacing a movable lens, which is a focus moving section, of a relay lens. A blue light reflection region is formed as part of the reflection/transmission film and the position of the blue light reflection region where the red light focus and the blue light focus are aligned is defined as reference position. The movable lens is displaced by an arbitrarily selected quantity from the reference position according to the target depth.

Abstract: An optical disc apparatus, which discriminates types of optical discs having different thicknesses of transparent layers by using the same wavelength of laser light, includes an aberration correction unit for correcting spherical aberration, an objective lens for condensing the laser beam onto a recording surface of an optical disc, an actuator for moving the objective lens with respect to the optical disc, a signal detection unit for delivering a focus error signal or a sum light signal, a control unit for controlling the aberration correction unit, the actuator and the signal detection unit.

Abstract: A focusing control method of an optical information storage media recording and/or reproduction apparatus controlling a focusing operation by moving an objective lens upwards or downwards in a direction towards or away from an optical information storage medium having a plurality of data layers includes receiving a focusing lead-in command signal to focus an optical beam on a target data layer, compensating for spherical aberration with respect to the target data layer, detecting a focus error signal based on an intensity of the optical beam reflected from the optical information storage medium and condensed by an optical detector, identifying the target data layer using an amplitude or a frequency of the focus error signal, and focusing the optical beam on the target data layer by moving the objective lens in an opposite direction from a direction in which the objective lens is initially moved.

Abstract: A method for determining a type of a disk and an optical storage apparatus thereof are provided. The method includes when the disk placed in the optical storage device is not a blank disk, determining whether the phases between a first signal and a second signal of the disk are the same or not; and determining that the disk is a low to high (LTH) data disk or a high to low data disk (HTL) data disk upon whether the phases of the first signal and the second signal are the same or not. Therefore, the reading parameters are correspondingly loaded in the optical storage device according to the type of the disk.

Abstract: An optical disk writing method including determining a writing scheme for recording information on the optical disc based on received tracking error signals. The method also includes moving an optical pickup across tracks of the optical disc while the optical pickup emits a laser beam, counting a number of the tracking error signal, and determining a storage capacity of the optical disc based on the counted number of tracking error signals.

Abstract: An optical disk apparatus according to the present invention is an optical disk apparatus for performing at least one of: recording data to a plurality of types of optical disks including a recordable optical disk and a read-only optical disk which are produced according to the BD specifications; and reproducing data from the optical disks. This apparatus includes: a means (506, 507) for irradiating a management area 502 of an optical disk 501 with a light beam while not performing tracking control, and generating a track position signal (push-pull TE or phase difference TE) from light which is reflected by the management area 502; and a disk determination means for determining, based on the track position signal obtained from the management area 502, whether the optical disk 501 mounted in the optical disk apparatus is a recordable optical disk or a read-only optical disk.

Abstract: In an HD-DVD, record densities are different between in a lead-in area and in a data area. On the other hand, in a DVD, the record densities of a lead-in area and a data area are equal. In discriminating an optical disc between the HD-DVD and the DVD, a light beam having a wavelength for the HD-DVD or for the DVD is projected onto the respective areas of the lead-in area and the data area, and a comparison is made between the amplitude of a tracking error (TE) signal obtained on the basis of reflected light from the lead-in area and that of a TE signal obtained on the basis of reflected light from the data area. When the difference between both the amplitudes is within a predetermined range, the optical disc is discriminated as the DVD, and when the difference between both the amplitudes is larger than the predetermined range, the optical disc is discriminated as the HD-DVD.

Abstract: An optical disk drive and a method for determining a disk type are described. The optical disk drive may be arranged to receive a radial error signal while an incident beam is focused onto the optical disk and before tracking the track, to analyze the radial error signal for detecting whether a wobble signal is present, indicating whether the track is wobbled, and to derive a disk type from the wobble signal, if present. The optical disk drive may additionally or alternatively be arranged to receive a central aperture signal while the incident beam is focused onto the optical disk and before tracking a track including a sequence of embossed pits, to analyze the signal amplitude of the central aperture signal, and to determine the disk type from at least a first variation of the signal amplitude of the central aperture signal as a function of time.

Abstract: A light source emits light with a first wavelength and light with a second wavelength longer than the first wavelength toward an optical disk from adjacent positions. An optical receiver detects light reflected from the optical disk. An astigmatism-generating element generates light used for focus control in a condition where a focusing position on one of two perpendicular cross sections including an optical axis of the light reflected from the optical disk is located ahead of the optical receiver and a focusing position on the other cross section is located behind the optical receiver are included. The astigmatism-generating element is a Fresnel mirror configured to include a plurality of reflecting mirrors. A level difference between the reflecting mirrors adjacent to each other is distributed in a range from a depth of substantially (natural number/2) times the first wavelength to (natural number/2) times the second wavelength.

Abstract: An IC provided in an optical disk device having an objective lens and a pickup for a disk. The IC has a circuit for holding a signal which drives the objective lens in a focus or tracking direction and for detecting the moving direction of the objective lens, and a circuit for generating a signal which applies an acceleration to the objective lens. When the objective lens passes through a defect on the disk, on the basis of the detected moving direction of the objective lens, the IC applies the acceleration alternately in plus and minus directions to the objective lens to make the objective lens stationary. As a result, after the defect passage, the objective lens can be quickly returned to a focused point or an on-track position and reproducing/recording operation can be resumed.

Abstract: An optical disc apparatus reproducing information on the basis of a standing wave recorded on a disc-like volume type recording medium includes: a first focus position adjusting unit configured to adjust the position of a focus on which a first light beam focuses inside a recording layer inside the volume type recording medium in the optical axis direction of the first light beam; a second focus position adjusting unit configured to adjust the position of a focus on which a second light beam focuses inside the recording layer in the optical axis direction of the second light beam; a controller configured to control the first focus position adjusting unit and the second focus position adjusting unit; and first and second detectors configured to detect the first and second reproduction light beams.

Abstract: A method for identifying a type of an optical disk includes the steps of: turning on a laser diode of an optical pickup and focusing light emitted from the laser diode on the optical disk; moving the optical pickup to obtain a plurality of servo signals; reading a specific servo signal from the servo signals; and determining the type of the optical disk according to the count of enabled times of the specific servo signal and a corresponding enabled time period.

Abstract: After an optical disk drive according to the present invention has been loaded with an optical disk and before the operation of recognizing the type of the given disk is finished, the drive presumes one of multiple types of candidate optical disks, from/on which data is readable and writable using a light beam with the shortest wavelength among the candidate disks, to be the disk being driven by the motor now and gets the beam for the presumed type of disk radiated from a light source (Step (A)). Next, the drive gets the disk spun at a rotational velocity that realizes a linear velocity equal to or higher than a standardized normal velocity when data is read from the presumed type of disk (Step (B)). Thereafter, the drive starts a focus control in a situation where the spot of the beam being formed on the disk is moving on the disk at the linear velocity equal to or higher than the normal velocity (Step (C)).