Funai Electric Company Ltd.

Hiroshi Mitsuda

Shinya Shimizu

The present invention optimizes recording power based on correct &#x3b2; value. Whether an average of modulation values between the 2-4th AUNs is equal to or less than 65% of an average of modulation values between the 5-7th AUNs or not is judged. Otherwise, the gradual emission is performed, the &#x3b2; value is measured, and then the following requirement is judged:(average of &#x3b2; values between 5-7th AUNs)&#x2212;(average of &#x3b2; values between 2-4th AUNs)&#x2267;0.18 If each requirement is satisfied, track shift is judged to occur. The recording area of high output is compared with the recording area of lower output to judge whether or not magnitude relation matches the correct magnitude relation. Also, whether the difference between the &#x3b2; value of high output and the &#x3b2; value of lower output is equal to or more than the predetermined value (0.18) or not is judged.

Optical disk recording device and optical disk recording method

In the first and second light-receiving regions equally divided into two in parallel with the track of the optical disc, the reflected light received from the optical disk is converted into electric signals and fed out by individual light-receiving regions. Then, the light-receiving ratio indicating the ratio of amounts of received light is calculated from the amplitude of the electric signal generated in the first light-receiving region and the amplitude of the electric signal generated in the second light-receiving region. Then, it is determined whether or not an absolute value of the light-receiving ratio is larger than a predetermined vale. When the absolute value is larger, the movement of the objective lens in a radial direction is corrected by incorporating a predetermined correction value.

Optical disc reproducing apparatus

A method for a focus error signal adjustment in an optical disk device which shapes a focus error signal and enables a high-accuracy focus servo is provided. In a DVD-RAM having an emboss data zone and a rewritable data zone, a focus error signal is generated with the DVD-RAM remaining still in a position where an emboss pit is not formed in the rewritable data zone, and a waveform of the FE signal is shaped so that the waveform is symmetrical with respect to a reference point. Then, the FE signal is generated in the emboss data zone and an amplitude of the FE signal is adjusted. The amplitude of the signal which is obtained by increasing the the amplitude of the FE signal whose amplitude is adjusted by approximately 6 dB is applied to the amplitude of the focus error signal in the rewritable data zone. Consequently, a high-accuracy focus servo based on the FE signal, whose amplitude is adjusted and waveform is shaped, can be achieved without an error caused by the emboss pit.

Method of focus error signal adjustment in optical disk device and optical disk drive

In an optical disc apparatus, the amplitude level of a focus error signal for performing focus search is measured, and in order to bring the measured amplitude level of the focus error signal to a target value, gains of focus servo drive amplifiers which amplify respective detection signals from four respective divided detection regions of an optical detector are set as initial values. As a result, the amplitude level of the focus error signal is adjusted at the target value. Next, the amplitude levels of the detection signals from the respective detection regions are measured, and the gains of the respective focus servo drive amplifiers are adjusted individually so that crosstalk can be cancelled based on the measured amplitude levels of the detection signals.

Optical disc apparatus

The present invention provides an optical disk recording and reproducing apparatus having a circuit configuration whereby it is possible to prevent tracking drive signals from being offset even when the temperature of a tracking actuator drive circuit is increased. The output resistance of a low-pass filteris composed of two serially connected resistors Rand R, the resistance of the former one Rof the serially connected resistors Rand Rbeing arranged to be lower than that of the latter one Rand a connecting point S between the former and latter resistors Rand Rbeing connected to the input side of an A/D port, whereby the potential difference between a tracking output portand the A/D portis reduced as much as possible, and thereby the reference voltage value stored in a reference voltage value storing meansapproaches an exact value as close as possible, which increases the accuracy of comparison results of a comparing meanssubstantially, and therefore a D/A conversion and offset cancel circuitcan output a tracking drive signal without offset.

Optical disk recording and reproducing apparatus

A disk reproducing apparatus for reproducing a digital audio signal recorded on a DVD or CD has a PLL portion for outputting a synchronizing signal in synchronism with the digital audio signal. When the CD is reproduced at double speed or higher, the PLL portion increases again while seeking tracks, and restores the gain if a predetermined time has passed after the end of seek.

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Osaka, Japan

Hiroshi Mitsuda