Hitachi-lg Data Storage, Inc.

Hitachi, Ltd.

Toshio Shoji

Koichi Watanabe

Yasuhiro Wada

Takakiyo Yasukawa

Naohito Ikeda

Toshio Saitoh

Mitsunori Kobayashi

It is desired that the overshooting and undershooting of optical pulse waveforms of optical pickups included in optical disk devices be reduced to improve the quality of recording. Among pulses to be recorded, the trailing edge of each last pulse and the leading edge of the subsequent erase top pulse are made to almost coincide with each other. Ratio a/b, where a is the difference between erase top pulse power level Pet and erasing power level Pe and b is the difference between recording power level Pw and the erasing power level Pe, is adjusted to realize an optical pulse waveform with reduced overshooting and undershooting for each of different recording media. Erase top pulse duration Tert is switched according to different recording speeds for different recording media.

Recording device and recording method for optical recording medium

In order to ensure recording quality while suppressing the adverse effects due to performance variations among apparatuses and disc radial positions on an optical disc, an optical disc apparatus according to the present invention performs, at the time of data recording, the steps of: acquiring a jitter value and &#x3b2; value from a reproduced signal based on laser light reflected from the optical disc in relation to a disc radial position; learning a &#x3b2; value when the acquired jitter value is a minimum as a target &#x3b2; value; and, if a jitter value acquired thereafter is larger than the minimum jitter value by a preset reference value or above, correcting recording power based on the magnitude relation and the difference between the &#x3b2; value associated with the acquired jitter value and the target &#x3b2; value or performing trial record processing.

Optical disc apparatus and data recording method thereof

There is provided an information recording and reproducing method and an apparatus for the same capable of optimizing the shift adjustment of a recording pulse recorded in an optical disk even at the time of recording information on the optical disk at a high speed. The shift adjustment value of the recording pulse optimized at a low speed recording on an optical disk is multiplied by a constant value to be taken as the optimum shift conditions of the recording pulse at the high speed recording.

Method of recording information on and reproducing information from optical disk and apparatus for the same

In a focus controlling method of a laser beam for an optical disk, achieving a stable focus drawing-in, lowering ill influences due to stray lights, detecting an electric signal, which is obtainable upon basis of a reflection light from the optical disk loaded, in advance, while executing a focus sweep operation of gradually approaching the laser to a recoding surface of the optical disk, at an unnecessary light detection gain being higher than a gain of normal operation, thereby counting a number of signals generated due to unnecessary lights; and thereafter, detecting the electric signal, which is obtainable upon basis of the reflection light from the optical disk loaded, and thereby conducting a focus drawing-in, by considering an electric signal, which is generated just after a number detected thereof reaches to the counted number of signals generated due to the unnecessary lights, to be a signal reflected from the recording surface of the optical disk loaded.

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Urayasu, Japan

Toshio Shoji