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AssigneeHitachi, Ltd.
InventorsMasaaki Kurebayashi, Akihiro Asada, Toshimitsu Kaku, Hideo Oonuki, Takashi Hoshino, Hidehiko Kandou
Estimating the term…
A laser drive (LD) unit 1 according to the present invention is provided with a laser drive waveform controller 6, into which information for setting the laser drive is entered from a controller 2, for generating a laser drive waveform on the basis of that information and supplying an indicated amperage; an LD current setting unit 7 for setting a laser drive current matching the indicated amperage; an LD current output unit 8 for varying the laser drive current on the basis of the laser drive waveform and supplying the current so varied to a laser diode 3; and a current setting corrector 9, into which a monitor signal obtained at the time of monitoring the laser beam emission from the laser diode 3 is monitored, for correcting the laser drive current set by the current setting unit 7 by using that monitor signal to adjust the power of the laser diode 3. The laser drive waveform controller 6, current setting unit 7, current output unit 8 and current setting corrector 9 are formed on the same substrate.
An optical disk drive apparatus so configured as to supply two-valued signals for controlling a laser drive circuit provided in an optical head from a controller via a flexible cable, the laser drive circuit comprising a laser drive waveform controller and a current output unit, wherein the laser drive circuit is so configured as to vary the power of a laser beam emitted by the optical head on the basis of an output current provided by the current output unit, the output current being varied based on a monitor signal resulting from monitoring the laser beam and on the laser drive waveform, the laser drive waveform being based on the two-valued signal and a clock signal supplied from the controller via the flexible cable, the laser drive waveform controller and the current output unit being formed on the same substrate.
An optical disk drive apparatus for recording or reproducing information by irradiating with a laser beam under the control of a laser drive circuit by a controller, the laser drive circuit comprising a laser drive waveform controller, wherein the laser drive circuit is so configured as to vary the power of a laser beam emitted by the optical head on the basis of a laser drive waveform produced by the laser drive waveform controller and on the basis of a monitor signal resulting from monitoring of the laser beam, the laser drive waveform being based on a two-valued signal and a clock signal supplied from the controller, and the controller and the laser drive circuit are formed on separate substrates.
A laser drive unit for varying a laser drive current on the basis of a laser drive waveform and supplying the laser drive current so varied to a laser, comprising:
A laser drive unit for varying a laser drive current on the basis of a laser drive waveform and supplying the laser drive current so varied to a laser, comprising:
A laser drive unit for varying a laser drive current on the basis of a laser drive waveform and supplying the laser drive current so varied to a laser, comprising:
A laser drive unit for varying a laser drive current on the basis of a laser drive waveform and supplying the laser drive current so varied to a laser, comprising:
An optical disk drive apparatus provided with an irradiating optical system for irradiating an optical disk with a laser beam from a laser diode and a detecting optical system, for detecting a beam resulting from reflection of the laser beam off the optical disk, and for recording information onto and reproducing information from the optical disk using the laser beam, comprising:
An optical disk drive apparatus provided with an irradiating optical system for irradiating an optical disk with a laser beam from a laser diode and a detecting optical system, for detecting a beam resulting from reflection of the laser beam off the optical disk, and for recording information onto and reproducing information from the optical disk using the laser beam, comprising:
An optical disk drive apparatus provided with an irradiating optical system for irradiating an optical disk with a laser beam from a laser diode and a detecting optical system for detecting a beam resulting from the reflection of the laser beam on the optical disk, for recording/reproducing information onto and from the optical disk using the laser beam, comprising:
An optical disk drive apparatus, provided with an irradiating optical system for irradiating an optical disk with a laser beam from a laser diode and a detecting optical system for detecting a beam resulting from the reflection of the laser beam on the optical disk, for recording/reproducing information onto and from the optical disk using the laser beam, comprising:
Dependencies are inferred from the claim text.