Nec Corporation

Kabushiki Kaisha Toshiba

Sanyo Electric Co., Ltd.

Nippon Electric Co., Ltd.

Shigeru Shimonou

Akihito Ogawa

Yutaka Kashihara

Yutaka Yamanaka

Hideki Takahashi

Tatsunori Ide

Tsuyoshi Yamamoto

Masato Fuma

Katsuki Hattori

Naotoshi Iwazawa

Hiroshi Inada

Masatsugu Ogawa

Tadashi Nomura

Toshiaki Iwanaga

Naoto Yamamoto

Masashi Kubota

Yoshinori Sasaki

Akihito Toshiba Corporation IPD Ogawa

Yutaka Toshiba Corporation IPD Kashihara

Hideki Toshiba Corporation IPD Takahashi

In an optical disk recording method of recording data onto a recordable optical disk which includes a data zone where data is recorded and a management data zone where management data indicating the recorded part of the data zone is recorded, an extended management data zone in which the management data is to be recorded is set in the data zone in response to an extension instruction.

Optical disk, optical disk recording method, and optical disk recording apparatus

An optical disc recording system includes a host apparatus configured to issue commands; and an optical disc recording apparatus configured to carry out a process corresponding to each of the commands, and to reply a response data to the command to the host apparatus. The host apparatus issues a record command as one of the commands to record a record data in an optical disc medium, and an optical disc recording apparatus records the record data in a data area in a predetermined format in response to the record command, wherein the optical disc comprises the data area and a first control data recording area. The optical disc recording apparatus additionally sets each of second control data recording areas in the data area in association with a command from the host apparatus as one of the commands, and a record status control data is recorded in the first or second control data recording area to indicate record status of the record data. At least a part of a second control data recording area associated data with at least one of the second control data recording areas is shared by the host apparatus and the optical disc recording apparatus.

Optical disc recording system

Data is recorded on an optical disc using a combination of a user data area where user data is recorded, a control data area for reproduction provided on an inner radius side of the user data area, and an outer guard zone provided on an outer radius side of the user data area as a unit of one recording operation. In this configuration, a track pitch TP of the optical disc is greater than or equal to 0.3 &#x3bc;m and smaller than or equal to 0.4 &#x3bc;m, and the width of the outer guard zone along a radius direction of the optical disc is greater than or equal to a value of (100&#xd7;TP) and smaller than or equal to a value of (125&#xd7;TP).

Optical disc recording method and apparatus

An optical disc medium includes a system area and a data area following the system area. A plurality of sets of an extended record control data area, a bordered area, and a border are possibly set in the data area continuously from the system area, and a first set of the plurality of sets does not include the extended record control data area. A user data is recorded in each of the bordered areas. In each of the plurality of sets other than the first set, a record control data associated with the user data which is recorded in the bordered area of the set is recorded in the extended record control data area.

Optical disc medium having extended record control data areas, optical disc apparatus using the same, and data recording method on the same

An optical disk medium in which a learning area can be expanded, an optical disk information recording method and an optical disk apparatus are provided. A first lead-in area and second lead-in area are provided on the inner side and outer side of a data area. The first lead-in area includes a first learning area, management information recording area and data connection area and the second lead-in area includes a protection area which protects the user data in the inner portion thereof and a second learning area which is provided on the outer side of the protection area and sets an optimum condition for an operation of recording data into the data area. An area in which information indicating the utilization state of the protection area is recorded is prepared in one of the management information recording area and data connection area.

Recording/reproducing method and recording/reproducing apparatus and optical disk

A positioning control apparatus for controlling a moving member to trace the position of a target member which almost equally repeats the position shift at a predetermined period comprises a position detector for detecting a relative position error, a first adder for adding a delay signal and a position error signal, a signal delay unit for outputting the delay signal which is obtained by delaying an output signal of the first adder at a period corresponding to the position shift of the target member, a second adder for adding the position error signal and the delay signal, a third adder for adding an output of the second adder and the delay signal via a filter, a compensating unit for performing the compensation for offset and/or the compensation for stabilization of the positioning control apparatus based on an output of the third adder, a drive unit for driving the moving member based on an output of the compensating unit, and a delay-amount setting unit for setting the amount of delay of a signal delayed by the signal delay unit.

Positioning control apparatus and method capable of reducing relative position error without increasing gain and frequency band of transfer characteristics of control system

A stepping motor has Hall elements which detect the position of the rotor and which output detection signals that have the same period as the excitation period, and which leads the position of the rotor by 90 degrees. The stepping motor is driven by the output of a drive current that is obtained by multiplying the detection signals output from the Hall elements with a torque command signal that controls the output torque of the stepping motor.

Stepping motor drive apparatus and stepping motor

An optical disk apparatus includes first and second objective lenses, a carriage, a moving mechanism, a fixed optical system, a main control section, track access control circuits, a first positional shift correction circuit, a second positional shift correction circuit, first and second driving members, an arithmetic circuit, and a correction member. The first and second driving members slightly drive the first and second objective lenses in a track crossing direction in accordance with the first and second positional shift correction signals, respectively. The first and second positional shift correction circuits count first and second track position signals to output first and second positional error signals with respect to a target track, and output the first and second positional shift correction signals to the first and second driving members based on the first and second positional error signals and the first and second track position signals, respectively. The arithmetic circuit calculates a difference between the first and second positional error signals to output an inter-beam positional shift signal. The correction member corrects one of the first and second positional shift correction signals based on the inter-beam positional shift signal.

Optical disk apparatus and track access control method for optical disk

Optical disk apparatus and track access control method utilizing

A stable and rapid track access control device capable of preventing, in the event of driving a converging lens of an optical disk drive to move a light beam, the lens from moving excessively. Assume that when the lens is driven to move the light beam, the movement of the lens exceeds a range which an optical lens can follow, increasing the positional deviation of the lens relative to the head. Then, the movement of the lens is so regulated as to equalize the speed of the lens and that of the head relative to each other.

Track access control device for an optical disk drive

To produce a tracking error signal (28) precisely indicating a positioning error of an optical beam with respect to one of recording tracks in a radial direction of an optical disk (12), a compensation section (31-36) compensates for a subtracted signal produced by subtraction between first and second electric output signals of first and second sensors (23 and 24) which receive first and second partial beams reflected from the optical disk by irradiating the optical disk by the optical beam. In the compensation section, an added signal is produced between the first and the second electric output signals. When the added signal is greater than a predetermined reference level, a comparator produces a compared result signal of a high level. Otherwise, the comparator produces the compared result signal of a low level. A sample-and-hold circuit passes the subtracted signal therethrough while the compared result signal has the high level. When the compared result signal turns from the high level to the low level, the circuit samples the subtracted signal into a sampled signal and holds the sampled signal while the compared result signal has the low level. The tracking error signal is produced by adding an inverted signal of the subtracted signal to a multiplied signal produced by multiplying output of the circuit by two.

Arrangement for producing precise tracking error signal for optical disk

Recording medium on which information is magneto-optically recorded is irradiated with a linearly polarized light beam. A light beam reflected from or passed through the recording medium is changed in phase by a wave plate. Through an analyzer the differently polarized components of the light beam from the wave plate are combined by aligning the polarizing directions of the light beam. The light intensities of the forward and backward parts of the moving direction of the recording medium in the far field of the light beam from the analyzer are detected by a photo detector. A difference between the detected signals of the forward and backward parts is generated to reproduce the information recorded on the recording medium. Furthermore, the light beam from the wave plate is splitted into two light beams linearly polarized in mutually orthogonal directions. Two light intensities of the two light beams for the forward and backward parts of the moving direction of the recording medium in the far field of the respective light beams are detected by two photo detectors. Two differences between the outputs from the two photo detectors are determined by two subtractors. A difference or sum between the two subtractors is determined and the information is reproduced on the basis of thus determined difference or sum.

Magneto-optical means for reading disks by comparing signals at leading

A controller for moving a transducer between recording tracks, comprising a current driven actuator for accelerating and decelerating the transducer for determined periods, position and velocity detectors of the transducer at the end of deceleration, error signal generators for the final position and velocity, and circuitry for increasing or decreasing periods of acceleration and deceleration based on the error signals.

Track access apparatus having a learning control for positioning a

An optical disk system comprising a head positioning system for positioning a head at a desired one of the tracks of an optical disk, and a tracking servo system for maintaining the head at the track by detecting a tracking error signal indicating deflection of the head from the track. In order to accurately position the head to the desired track, a track crossing signal deriving circuit derives an alternating signal component having a frequency corresponding to track crossing of the head from the tracking error signal as a track crossing signal. The track crossing signal is converted to a pulse signal which is counted to produce a counted number as a track crossing number. The track crossing number is compared with a desired track number previously set and a position error signal is produced. A head driving motor is driven until the position error signal becomes zero so that the head is correctly positioned at the desired track. The track crossing signal is converted into a voltage signal as a velocity signal. A slew rate of the track crossing signal deriving circuit is controlled by the velocity signal so that the track crossing signal is reliably derived even if the track crossing velocity increases.

Head positioning system for use in information recording/reproducing

A magneto-optical head for reading information from a recording medium, the head having a laser-based optical system that comprises two light paths, a first path from the source to and continuing through or reflecting from medium and a second path in a different direction which directs light from the medium to a detector. The second path includes a dual prism multiplying element (Wollaston prism) for dividing the reflected beam into three distinctly oriented beams, and a multi division photodetector for detecting a servo signal by the astigmatism method and an information signal by a differential polarization method.

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Tokyo, Japan

Shigeru Shimonou