Hitachi Media Electronics Co., Ltd.

Other

Hitachi, Ltd.

Nobuyuki Maeda

Fumio Isshiki

Takeshi Shimano

Takahiro Kurokawa

Kunikazu Ohnishi

Michio Miura

Shinji Fujita

Seiichi Kato

Shinya Fujimori

Akio Yabe

A rewritable optical disk apparatus, optical information recording and reproducing apparatus or the like is allowed to automatically and properly adjust the optical system to the optimum focal condition regardless of the readout signal detector's positional error and the residual aberration in the optical system. The spherical aberration and defocus are coarsely adjusted using the amplitude (PP amplitude) of the tracking error signal and then finely adjusted using the amplitude (RF amplitude) of the readout signal. Since the spherical aberration can properly be adjusted, it is possible to raise the reliability of the readout signal.

Optical information recording apparatus

A method and an optical disk apparatus that can accurately and stably correct the spherical aberration even for a blank write-once optical disk and can detect a spherical aberration error signal with a simple construction of parts in real time. In a blank write-once disk, the tracking servo is switched to an inoperative state, push-pull signals from outputs of the photodetectorare detected in a state of 'in focus' and in a state of 'out focus,' respectively, by a push-pull signal generation circuit, and.the amplitudes of these push-pull signals are subjected to difference calculation in a spherical aberration error detectorto obtain a spherical aberration error signal A. Then, the spherical aberration is corrected with this spherical aberration error signal A, and subsequently a specific pattern signal is recorded in a trial writing area, this signal is reproduced in the state of &#x201c;in focus&#x201d; and in the state of &#x201c;out focus,&#x201d; respectively, the amplitude of each reproduced signal is acquired by a reproduced signal generation circuit, these amplitudes are subjected to difference calculation in the spherical aberration error detectorto obtain a spherical aberration error signal B. The spherical aberration is corrected with this.

Optical disk apparatus and method for recording and reproducing an optical disk

According to the invention, techniques for minimizing power consumption in optical disk drives. Embodiments according to the present invention can provide disk drives with optimal positioning of a fixing part of an objective lens driving unit incorporated therein. Spatial location of magnets can also be determined in order to reduce the power consumption and the torsion of the lens.

Disk drive apparatus having improved power consumption

Growing community of inventors

Yokohama, Japan

Nobuyuki Maeda