Abstract: Each drive in a cluster is organized into splits of a single size. The splits are used as protection group members for a selected RAID level. Individual clusters can be scaled up with a number of new drives that is less than the number of protection group members for the RAID level by redistributing some data/parity to splits of the new drives. Splits are selected for redistribution such that new protection groups are created. If the number of new drives is equal to or greater than the number of protection group members for the RAID level, then new clusters may be created using the new drives. Any remaining drives are used to scale-up individual clusters.

Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Abstract: A device for processing a signal includes a processor stage configured to filter the signal present in a frequency-domain representation by a filter with a filter characteristic in order to obtain a filtered signal, to provide the filtered or a signal derived from the filtered signal with a frequency-domain window function, in order to obtain a windowed signal, wherein providing has multiplications of frequency-domain window coefficients of the frequency-domain window function by spectral values of the filtered signal or the signal derived from the filtered signal in order to obtain multiplication results, and summing up the multiplication results. Further, the device has a converter for converting the windowed signal or a signal determined using the windowed signal to a time domain in order to obtain the processed signal.

Abstract: A device for processing a signal includes a processor stage configured to filter the signal present in a frequency-domain representation by a filter with a filter characteristic in order to obtain a filtered signal, to provide the filtered or a signal derived from the filtered signal with a frequency-domain window function, in order to obtain a windowed signed, wherein providing has multiplications of frequency-domain window coefficients of the frequency-domain window function by spectral values of the filtered signal or the signal derived from the filtered signal in order to obtain multiplication results, and summing up the multiplication results. Further, the device has a converter for converting the windowed signal or a signal determined using the windowed signal to a time domain in order to obtain the processed signal.

Abstract: A digital polar transmitter arrangement having a digital front end (DFE) and a transmit chain is disclosed. The DFE is configured to resample a baseband signal relative to a carrier frequency at a carrier frequency related sample rate, calculate zero crossing positions of the resampled signal, generate delay to time converter (DTC) commands based on the zero crossing positions, calculate amplitude values for the zero crossing positions and generate dynamic phase alignment (DPA) commands based on the amplitude values. The transmit chain is configured to generate an output signal having amplitude and phase modulation based on the DTC and DPA commands.

Abstract: A management system manages a plurality of data units constituting schemas of a database in a storage device, which includes a plurality of first storage device sets having a plurality of storage areas. An ordered schema constituted of the plurality of data units having order properties defining respective orders is included in the schemas. When a second storage device set, which is a set of one or more second storage devices and in which each of the storage areas is a free storage area, is added to the first storage device set, the management system migrates two or more data units not consecutive in the order among a plurality of data units stored in the plurality of storage areas in the first storage device set respectively from at least the one first storage device set to the free storage areas of the second storage device set.

Abstract: A computer-implemented method, according to one embodiment, includes, for a particular data read clock value, generating a series of symmetrical square wave signals, each having a frequency that is a different fraction of the data read clock frequency. Anti-aliasing filtering is performed on each of the symmetrical square wave signals using predefined anti-aliasing settings. The filtered symmetrical square wave signals are passed through a band pass filter, the band pass filter being set to pass a single harmonic frequency of each of the symmetrical square wave signals. An amplitude of each of the band pass filtered symmetrical square wave signals is measured. In response to the amplitudes of the symmetrical square wave signals being within a predefined range, the anti-aliasing settings are stored. In response to the amplitudes of the symmetrical square wave signals being outside the predefined range, the anti-aliasing settings are changed, and the method is repeated.

Abstract: The present invention discloses an audio playing system for protecting a storage medium of an electrical device. The audio playing system includes a detecting unit, a processing unit, an adjusting module and a playing module. The detecting unit detects vibration of the electrical device to generate a detection signal corresponding to the vibration. The processing unit compares the detection signal with the tolerable vibration value of the storage medium to generate a comparison result, and generates an adjustment signal according to the comparison result. The adjusting module adjusts an audio file according to the adjustment signal to generate an adjusted audio file. The playing module plays the adjusted audio file. The present invention also discloses an audio playing method for protecting a storage medium of an electrical device.

Abstract: According to one embodiment, in an information recording medium including a plurality of data layers, at least one pre-format area is provided on each of the data layers and is circumferentially divided into a plurality of segments. Management information including data layer identification information for identifying the data layers is recorded in at least one of the segments in each of the data layers, using the marks include BCA marks extending radially uniformly. On adjacent ones of the data layers, the BCA marks associated with the management information are recorded in differently positioned segments which are not opposed to each other.

Abstract: A wobble determining apparatus is provided with: a calculating device for calculating (i) a first time required until reaching a number of revolutions of a motor which allows a predetermined linear velocity, and (ii) a second time required to move an optical head to a position which allows the predetermined linear velocity, on the basis of the number of revolutions of the motor and the position of the optical head; a judging device for judging whether to keep the optical head in accordance with the calculated first time and the calculated second time; and a controlling device for controlling a moving device not to move the optical head if it is judged to keep the optical head, and for controlling the moving device to move the optical head to the position which allows the predetermined linear velocity if it is judged not to keep the optical head.

Abstract: A start-up method of an optical disk drive, comprising: starting to accelerate a spindle motor after initializing a digital signal processor; starting an laser diode driver of an optical pickup head after the spindle motor starts accelerating; and starting a servo control of the optical pickup head. During the step of starting the laser diode driver, the spindle motor is accelerating.

Abstract: The disclosure is related to systems and methods for adaptive seek latency in a rotating storage device. In one example, a servo control circuit can be configured to determine a seek latency and provide the seek latency to another controller or control circuit that is configured to implement the seek latency. Further, the servo control circuit can calculate the seek latency based on a measurement of a variable condition of a device and the servo controller can adjust the seek latency as the condition varies. In some examples, the variable condition may include power measurements, temperature measurements, a fault rate, other conditions, or any combination thereof. Also, different algorithms for calculating the seek latency may be implemented based on a selected goal of the system, such as power savings or reduced head vibration.

Abstract: The optical disc device has a circuit which forms a focus error signal for focus servo control based on reflection light from an optical disc exposed to laser light. Also, the device has a data processing unit which can control by feedback a position to which an objective lens is moved by a focusing actuator based on a focus error signal. In label printing, the data processing unit controls, by feedforward, a position to which the objective lens is moved by the focusing actuator based on control data for label printing. The operation resolution of the focusing actuator in feedforward control is made higher than that in feedback control. Thus, an intended position control accuracy is achieved in feedforward control. For instance, in feedforward control, the gain of the driver circuit for the focusing actuator is switched to a smaller one in comparison to that in feedback control.

Abstract: A start-up method of an optical disk drive, comprising: starting to accelerate a spindle motor after initializing a digital signal processor; starting an laser diode driver of an optical pickup head after the spindle motor starts accelerating; and starting a servo control of the optical pickup head. During the step of starting the laser diode driver, the spindle motor is accelerating.

Abstract: An exemplary method of controlling an optical storage apparatus includes: driving a first mechanical mechanism of the optical storage apparatus by applying a first control signal to the first mechanical mechanism, wherein a second mechanical mechanism of the optical storage apparatus is inactive while the first mechanical mechanism is operating in response to the first control signal; adjusting the first control signal applied to the first mechanical mechanism when the second mechanical mechanism is requested to be active; and driving the second mechanical mechanism by applying a second control signal to the second mechanical mechanism while the first mechanical mechanism is operating in response to the adjusted first control signal.

Abstract: 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.

Abstract: A method and system that provides for execution of a first calibration sequence, such as upon initialization of a system, to establish an operation value, which utilizes an algorithm intended to be exhaustive, and executing a second calibration sequence from time to time, to measure drift in the parameter, and to update the operation value in response to the measured drift. The second calibration sequence utilizes less resources of the communication channel than does the first calibration sequence. In one embodiment, the first calibration sequence for measurement and convergence on the operation value utilizes long calibration patterns, such as codes that are greater than 30 bytes, or pseudorandom bit sequences having lengths of 2N?1 bits, where N is equal to or greater than 7, while the second calibration sequence utilizes short calibration patterns, such as fixed codes less than 16 bytes, and for example as short as 2 bytes long.

Abstract: An approach is described that allows an optical disc drive to accurately verify the power level of irradiation beam power levels associated a write strategy used in high speed, high density optical disc media formats using a front monitor diode with a relatively slow rise time and/or relative slow fall time compared to the clock cycle speed of the write strategy signal. A portion of encoded data to be written to an optical disc media may be overwritten to include a predetermined data pattern. During write strategy processing of the data, the predetermined data pattern is replaced with a constant write strategy power level. The constant write strategy output placed within the write strategy signal may control the optical disc drive laser to emit a constant irradiation beam for a duration sufficiently long to allow the front monitor diode to obtain an accurate measure of the irradiation beam power level.

Abstract: An optical disk device for recording/reproducing information on/from a multi-layer optical disk moves a light focusing point for several layers by one focus jump. The optical disk device includes a controller to detect a level of a focus error signal to change an output level of a focus drive signal, and the controller changes timing to change the output level of the focus drive signal based on the number of layers for the focus jump.

Abstract: In a recording system (1), a personal computer (20) reads out boot information from an optical disc (31) in a predetermined order and records elements of the boot information in contiguous areas on the optical disc (32). In order to thus operate, the personal computer (20) refers to access records before reading out the boot information from the optical disc (31). The access records are generated by a protocol analyzer (11) at a start-up of a personal computer (10). Further, for each of the elements indicated by the access records, the personal computer (20) records, on the optical disc (32), an address conversion table in which that area on an optical disc (31) in which the element is recorded and that area on the optical disc (32) in which the element is recorded are correlated with each other.

Abstract: Method and device for generating a control voltage for a position actuator of a disk drive system for displacing a lens of a pick-up unit to a given X-position. The actuator is operated by an open loop control system. First, parameters of the control system are calibrated so that the control system produces a control voltage (Va) from an input position signal (Xact_setp). Then, the control voltage is processed in a feed forward system for generating a processed control signal (Va_p) which is fed to the position actuator for displacing said lens to the X-position. A Z-value corresponding to the axial distance of the lens from a calibrated axial position and a temperature of the pick-up unit are measured. The position actuator operates according to the formula: Xdc=Va—p*K(Temp,Z)/(R(Temp)*C(Temp,Z)).

Abstract: A tilt can be detected highly accurately by minimizing the tilt detection error. An optical head includes: an objective lens for converging a light beam from a light source onto an optical disc; a photodetector section receiving the beam, reflected from the disc, at divided areas on its photodetection plane and outputting light detection signals from those areas; and a tilt detecting section for detecting a relative tilt between the lens and disc based on the detection signals.

Abstract: A servo control device includes: a phase compensator configured to generate a plurality of types of control values for controlling a driver based on a signal output from an optical pickup, and output the control values; and a transfer data generator configured to serially transfer the control values to the driver. The phase compensator sends, to the transfer data generator, a notification that the phase compensator has output a control value which needs to be sent with a reduced delay among the control values. In response to the notification, the transfer data generator determines whether or not the transfer data generator is transferring one of the control values, and if the transfer data generator is not transferring one of the control values, the transfer data generator starts transferring a control value associated with the notification among the control values.

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: A method and apparatus identifying a type of a recordable disc according to whether a land pre-pit (LPP) is formed on the disc. The apparatus includes an RF (radio frequency) amplifier amplifying light reflected by the disc to a predetermined value; an LPP signal detector detecting an LPP (Land Pre-Pit) signal from output signals of the RF amplifier; and a system controller identifying a type of the disc according to whether the LPP signal is detected by the LPP signal detector. Since a disc type is discriminated and operational conditions of a disc drive are adequately set during an early stage of a disc driving period, a lead-in time of a disc can be reduced.

Abstract: A servo control signal generation device for discriminating a kind of an optical disk, changing over between top and bottom envelope signals of an RF signal, and generating a defect signal and a mirror signal includes an RF generator for generating the RF signal from reflected light of an optical disk, a disk discriminator for discriminating a kind of the optical disk from the RF signal, and a top envelope generator and a bottom envelope generator respectively for generating the top and bottom envelope signals of the RF signal. If the disk has reflectance after recording which is lower than that before recording, the defect and mirror signals are generated respectively from the top and bottom envelope signals. If the disk has reflectance after recording which is higher than that before recording, the defect and mirror signals are generated respectively from the bottom and top envelope signals.

Abstract: An apparatus 100 according to the present invention is designed to read and/or write data from/on an information recording medium 1 using near-field light. The apparatus 100 includes: a light source 3 for emitting laser light; a condensing section 7 for producing the near-field light based on the laser light; a detecting section 22, 23 for detecting the relative positions of the condensing section 7 and the information recording medium 1; and a control section 14 for controlling the position of the condensing section 7. In starting a gap servo operation, the control section 14 controls the position of the condensing section 7 so that the gap servo operation is started at a different location on the information recording medium 1 from any other location where the gap servo operation has ever been started.

Abstract: An optical disc drive apparatus includes: a first optical pickup and a second optical pickup which record data on an optical disc and reproduce data recorded on the optical disc; a slide mechanism which has the first and second optical pickups mounted thereon to slide the first and second optical pickups in a radial direction of the optical disc; a seek command receiver which receives a seek command; a first optical pickup controller which causes the first optical pickup to perform a search on the basis of the seek command received by the seek command receiver; a slide mechanism controller which controls the slide mechanism on the basis of the seek command received by the seek command receiver; and a second optical pickup controller which turns off a tracking servo of the second optical pickup when the first and second optical pickups are slid by the slide mechanism.

Abstract: An information recording medium includes a first information recording layer and a second information recording layer. The first information recording layer is formed at a laser beam entrance surface, and is configured so that information can be recorded thereupon and/or reproduced therefrom using a first objective lens having a numerical aperture NA1 and laser beam of a wavelength ?1. The second information recording layer is formed so as to have a distance to the laser beam entrance surface of 0.05 mm to 1.2 mm and is configured so that information can be recorded thereupon and/or reproduced therefrom using a second objective lens having a numerical aperture NA2 and laser beam of a wavelength ?2. When a diffraction limit ?2, determined by numerical aperture NA2 and wavelength ?2, is taken as ?2=0.61×?2/NA2, a track pitch Tp1 of a track formed on the first information recording layer is Tp1<?2.

Abstract: In an optical disc device, a way of canceling a lens shift due to an electric offset of an output of a tracking actuator driving circuit is desired. A tracking servo control circuit contains a first operation mode for setting an output current of the tracking actuator driving circuit to generally zero and a second operation mode for supplying a predetermined potential to the input. An average potential of a push-pull signal detected in the first operation mode is acquired. An object lens is moved by a predetermined amount in both radial directions by changing a potential supplied in the second mode to acquire correlative relationship between average potential of a push-pull signal relative to a lens movement amount and the supplied potential. An offset amount is acquired from the potential and the correlative relationship to cancel the offset.

Abstract: According to the present invention, even if tracking fails during reproduction of information from an optical disk and a movement is made to an adjoining track, the reliability of data to be transferred is improved and a countermeasure can be taken immediately. An unrecorded area decision unit decides based on the amplitude of a reproduction signal whether a block concerned is a recorded area or an unrecorded area. A track-off detection unit monitors a tracking servo signal, detects occurrence of a tracking failure, and registers a block, which is recognized as an area where the tracking failure has occurred. If the block is an unrecorded area and recognized as an area where a tracking failure has occurred, reproduction is ceased but data signifying that the block is an unrecorded area is not transferred to an upper-level system and retry is performed to achieve reproduction.

Abstract: The present invention discloses a method and an apparatus for compensating astigmatism in an optical storage system. Firstly, the optical storage system focuses on an optical disc and proceeds track seeking. While track seeking, the astigmatism compensator continues adjusting and an astigmatism index signal is also measured. At last, an optimal astigmatism compensated value of the astigmatism compensator is acquired based on the measured result of the astigmatism index signal.

Abstract: The present invention achieves higher precision and lower power consumption by reducing semiconductor chip occupation area. A semiconductor integrated circuit which can be mounted on an optical disk device has: a wobble signal generating circuit capable of receiving first, second, third, and fourth light reception output signals A, B, C, and D of a light receiving element in an optical pickup and detecting a wobble in a recordable disk; a differential phase detection signal (DPD) generating circuit for tracking an unrecordable disk; and two A/D converters and an arithmetic circuit.

Abstract: Methods and systems are described for correcting repeatable runout. In one aspect, an open loop tracking signal is received and squared. A discrete Fourier transform (DFT) of the squared open loop tracking signal is obtained. A velocity magnitude and an absolute value of the phase of the open loop tracking signal is determined. A RRO correction signal is iteratively constructed by performing a partial correction based on an initial phase selected and an initial velocity amplitude, measuring a relative velocity amplitude, performing a partial control correction using the initial phase and relative velocity amplitude if the amplitude is smaller than an initial amplitude; performing a partial control correction using the initial phase and the relative velocity amplitude if the amplitude is smaller than an initial amplitude, and repeating the above steps until a tracking controller can perform closed loop control of the track to optical pickup unit velocity.

Abstract: An optical disc apparatus includes an optical pickup, a signal generation section which generates a control signal from an electrical signal, and a main control section which controls the optical pickup such that, during a spin-up operation of an optical disc, the optical disc is discriminated to be a multiple-layer disc with three or more layers and address information is successfully acquired from the optical disc, the optical pickup irradiates the optical disc with a light beam at a light emission power for a multiple-layer disc with three or more layers. However, if disc information is not successfully acquired, the main control section controls the optical pickup to try again to acquire the disc information at the light emission power for a multiple-layer disc with three or more layers.

Abstract: A processing circuit for optical data is provided. The processing circuit includes a signal-processing module and a radio frequency (RF) signal-summing module. The signal-processing module averages and filters the data signals to obtain a low-frequency signal. The RF signal-summing module receives the data signals and the low-frequency signal, sums the data signals to obtain a summed data signal, and subtracts the low-frequency signal from the summed data signal to obtain a RF summing signal.

Abstract: [Object] To enable stable void recording to be performed with lower power than in a case where a conventional void recording method that records hole marks (voids) in a bulk layer is adopted. [Solving Means] First laser light is irradiated onto an optical recording medium in which a plurality of resin layers are formed while the first laser light is focused on a boundary surface of the resin layers, to thus record hole marks onto the boundary surface. Since a recording sensitivity of the hole marks is enhanced at the boundary surface of the resin layers, by recording hole marks onto the boundary surface as described above, laser power requisite for recording can be suppressed as compared to the conventional art. As a result, it becomes unnecessary to use a special laser such as a short-pulse laser, and even if a CW laser (CW: Continuous Wave) is used, a recording speed does not need to be sacrificed.

Abstract: An optical disk apparatus according to the present invention includes: a controller 111, which receives an instruction that a layer-to-layer jump be performed from a current layer to a target layer; a layer-to-layer jump control section 146, which adjusts a spherical aberration correction value to the target layer and then gets the layer-to-layer jump attempted; a decision section 146 for determining whether the layer-to-layer jump has been carried out successfully; and a layer determining section 146 for determining, if the focus position has been set on a non-target storage layer as a result of the layer-to-layer jump, where the non-target storage layer is located in the optical disk. The layer-to-layer jump control section 146 shifts the focus position of the light beam from that non-target storage layer to the target layer by reference to information indicating which of the multiple storage layers the non-target storage layer is.

Abstract: A device for detecting wobbles on an optical disc is provided, where the device is utilized for generating a wobble signal according to a plurality of detection signals. The device includes an analog signal processing circuit, a pair of analog-to-digital converters (ADCs), and a digital signal processing circuit. The analog signal processing circuit is arranged to perform analog signal processing on the detection signals to generate a plurality of output signals. In addition, the pair of ADCs are arranged to digitalize the output signals to generate a plurality of digital values. Additionally, the digital signal processing circuit is arranged to perform digital signal processing on the digital values and generate an arithmetic output, where the arithmetic output is utilized for generating the wobble signal or utilized as the wobble signal. An associated method for detecting wobbles on an optical disc is further provided.

Abstract: A calibration circuit and a calibration method thereof for data recovery are provided. The calibration circuit includes an amplitude detector, a period detector, and a compensation circuit. The amplitude detector samples amplitudes of a data signal according to a zero-crossing signal and outputs an amplitude signal accordingly. The period detector counts a clock signal according to the zero-crossing signal and outputs a period signal accordingly. The compensation circuit receives the amplitude signal, the period signal, and the data signal. The compensation circuit adjusts a phase of the data signal by calculating differences between a reference signal and the amplitude signal and between the reference signal and the period signal and outputs a calibrated data signal accordingly. Accordingly, a better recognition performance on the data signal is achieved by calibrating the data signal in real-time.

Abstract: A power saving method and a power saving system are applied in an optical disk drive. The power saving system comprises a power controlling unit for differentiating the specific sets of circuits not being used at a specific operation rate and powering them down. The sets of circuits not being used will be powered up while the associated operation rate at which they are required to operate is nearly started.

Abstract: In an optical disk recording apparatus, a monitor monitors a recording power of a laser light. A laser control circuit enables a laser diode to perform test recording while using the monitor to monitor the recording power of the laser light and while controlling a laser drive voltage, so that the monitored recording power reaches a given reference value during the test recording. A voltage measurement section measures the laser drive voltage when the recording power of the laser light reaches the reference value. A calculation section calculates an initial laser drive voltage from the reference value of the recording power and the measured laser drive voltage corresponding to the reference value. A main controller allows the laser control circuit to set the calculated initial laser drive voltage and to start the recording while supplying the laser control circuit with the target value so that an actual recording power of the laser light promptly reaches the target value during the course of the recording.

Abstract: An optical disc apparatus, for executing recording or reproducing on an optical disc having at least two recording/reproducing layers, includes an optical pickup, having a sphere aberration compensating portion, an objective lens, a driver portion, and an obtaining portion. The sphere aberration compensating portion sets up a compensation volume corresponding to an intermediate position laying between a deepest layer and a most front layer from the optical pickup, and the driver portion drives the objective lens in a direction approaching to the optical disc in accordance with the set compensation volume. When the sphere aberration compensating portion sets up the compensation volume corresponding to the deepest layer, and when the objective lens is driven in a direction approaching the optical disc, the driver portion drives the objective lens in a direction of separating from the optical disc.

Abstract: A control apparatus is provided for controlling an access means for accessing a recording medium containing at least one area so that the access means accesses the at least one area. The apparatus comprises a means for determining whether or not at least one first recorded area storing data is included in the at least one area, and a means for controlling the access means. When it is determined that the at least one first recorded area is included in the at least one area, the control means controls the access means based on a result of accessing the at least one first recorded area.

Abstract: Disclosed herein are an optical recording medium driving device and an additional recording method, which performs tracking servo control for moving an objective lens in a direction orthogonal to a tangential direction of a guide track so that a guide tracking error signal is decreased with respect to a guide track of a guide layer separation type recording medium, detects an additional recording start position subsequent to a recorded track if the recorded track is present in a recording layer of the optical recording medium, generates a tracking correction signal according to the reproduction tracking error signal upon tracking servo control of the recorded track just before the additional recording start position, and corrects tracking servo control according to the tracking correction signal upon additional recording start.

Abstract: An optical pickup apparatus comprising: a diffraction grating that a laser beam enters, the diffraction grating being configured to generate a main beam that is 0th order light and sub-beams that are +1st order diffracted light and ?1st order diffracted light; an objective lens configured to focus the main beam and the sub-beams onto a signal recording layer; a main-beam light-receiving portion that the main beam reflected by the signal recording layer is applied to; and sub-beam light-receiving portions that the sub-beams reflected by the signal recording layer are respectively applied to, each light-receiving area of the sub-beam light-receiving portions being smaller than a light-receiving area of the main-beam light-receiving portion.

Abstract: There is a need to accurately lock focus of a laser beam onto a target data layer of a multilayer optical disc. The above need can be addressed by, for example, performing a focus lock operation after a spherical aberration correction amount is set in such a way as to make smaller the ratio of the focus error signal waveform amplitude at the data layer adjacent to a target data layer through which a laser beam passes earlier than through the target data layer to the focus error signal waveform amplitude at the target data layer than that when the spherical aberration correction amount is set so as to be optimal for the target data layer.

Abstract: The present invention provides an optical disc drive and a method for changing a mode in the same. In an embodiment of the present invention, it can be determined whether to change a mode of the optical disc drive based on a command sent from a host connected through an interface. If a predetermined command is sent from the host within a predetermined time after the optical disc drive is newly connected to the host or power is supplied to the optical disc drive while the optical disc drive is already connected to the host, the mode may be switched into a first mode of connecting to a computer, and otherwise the mode may be switched into a second mode of connecting to a host with a function of playing data of a medium connected through the interface. Accordingly, the optical disc drive can automatically change its operation mode.

Abstract: The present invention sets forth a power saving method and a power saving system applied in an optical disk drive. The power saving system comprises a central processing unit, a spindle motor, an optical pick-up unit, an analog portion of control circuits and a digital portion of control circuits. Each of the analog or digital portions of control circuits can be divided into several sets of circuits. Each set of circuits is coupled to an associated operation mode of the optical disk drive. The power saving system further comprises a power controlling unit for differentiating the specific sets of circuits not being used in the specific operation mode and powering them down. The sets of circuits not being used will be powered up while the associated operation mode in which they are required to operate is nearly started. The present invention also provides a power saving method of powering down the sets of circuits not being used relative to a specific operation mode of the optical disk drive.

Abstract: The present invention provides an optical disk apparatus and a focus jump method capable of reliably performing a focus jump by appropriately obtaining the amplitude of a signal such as a focus error signal in a multilayer optical disk. An optical disk includes jump areas which are provided separately from data areas and at which a focus jump is performed. When a focus jump is performed, an optical pickup is moved to the jump area, and the laser power level of the optical pickup is changed and set in accordance with a target layer to which the focus is jumped. A focus position is allowed to reach the target layer by counting the number of times of intersecting with recording layers using a reflected light from the optical disk while performing a focus sweep of an objective lens in the optical pickup.