Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Toshiya Akagi

Yuji Hisakado

Chikashi Inokuchi

Yukihiro Yamasaki

Yoshiyuki Miyabata

Shinichi Konishi

Takeshi Nakajima

Harumitsu Miyashita

Atsushi Miyazaki

Takashi Ishida

Mamoru Shoji

Shigeru Furumiya

Toshihiko Takahashi

Toyoji Gushima

Kenichi Tatehara

Kiyoshi Nakamori

Ariaki Ito

Atsushi Nakamura

Hiroyuki Yamaguchi

Junichi Minamino

Hironori Deguchi

Yuichi Takahashi

Yasuhiro Wada

Yuichi Kamioka

Kenji Takauchi

Yukinori Okazaki

Yasuhiro Tai

Katsuo Hori

Yasushi Ouchi

Eisuke Ishibashi

Shinya Shimizu

Yasuhiro Honda

A recording method for an optical disc drive and an optical disc drive wherein a surrounding temperature is measured by a temperature sensor serving as temperature measuring device, a set surrounding temperature is correlated with a set recording rate by using a data table stored in an internal memory of a controller serving as correlating device, and a recording rate is changed by a digital signal processing portion serving as recording control device based on the surrounding temperature measuring result and the correlating result. The recording rate is changed by changing a ratio of a recording operation time and a recording-stop operation time with alternately repeating a recording operation and a recording-stop operation at as low a laser beam output as playback.

Optical disc drive and recording method for optical disc drive

The sector synchronism of a timing generation section for generating data recording/reproducing timing is corrected at the address-mark detection timing of an address-mark detection section. Moreover, even if only one piece of address information having no error is not reproduced in the sector concerned, when at least one piece of address information having no error is reproduced in any of a predetermined number of sectors preceding the subject sector and at least one address mark is detected in the subject sector, the data recording/reproducing is permitted, and thus, the data is recorded/reproduced at a high speed and a high reliability even if an error rate of a physical address is deteriorated.

Information recording/reproducing device using optical disk and method therefor and information recording system and information recording method

A recording apparatus for recording modulated data on a rewritable recording medium includes a data modulation section for modulating data in accordance with a prescribed modulation rule; a parameter value changing section for changing at least one parameter value of the prescribed modulation rule; and a recording section for recording the data modulated in accordance with the prescribed modulation rule on the recording medium.

Recording apparatus and recording method for recording data to a rewritable recording medium, and rewritable recording medium

A ratio of an erase current and a peak current when starting recording is defined as K=iER/iPK (S), and iER11 is set equal to K&#xd7;iPK, and an ideal value iERof an erase current that should be increased according to a temperature change is determined (S). A value obtained by subtracting a current iBT at a bottom level emission intensity when starting recording from a current at an erase level emission intensity after the temperature rises is defined as iER. By measuring this iER, an ideal value iERof the erase current is subtracted from iER, and the resultant current is defined as iBT(S). This iBTis set as an adjustment value of the bottom current, and a value obtained by adding this adjustment value to a bottom current when starting recording is set as a bottom current after change.

Optical disk device and emission current adjusting method for the same

A power control device for controlling a power of a light source of an optical beam directed to an optical medium. The power control device includes a reflected light detector for detecting reflected light from the optical medium when irradiated by an optical beam which is following a track; an arithmetic unit for calculating from the reflected light a transmissivity of light transmitted from a disk surface to a recording layer or an amount of directed light on the recording layer of the medium; and power control means for controlling the power of the light source for emission based on a calculation result produced by the arithmetic unit.

Laser power controller and optical disk device

An optical disk drive and recording power determination method determine the optimum power with consideration for the recording state of a base layer track when determining the optimum power by test recording before recording user data. After recording at a second recording power that is higher than a first recording power by a specific amount, recording is performed at a third recording power that is lower than the first recording power by a specific amount, and the first recording power is set to the recording power for data recording when a specified playback signal quality is achieved.

Optical disk device and recording power determining method

An optical disc drive usable with discs to which data is continuously recorded and discs having a sector format can quickly resume playback signal output after passing imperfection causing potential reading errors, and plays disc with few read errors. A detection signal generator detects DC level fluctuation in the playback signal read from the disc and generates a detection signal tracking the DC level fluctuation. A selector selects a detection signal or a null signal without valid polarity based on the detection signal generated by the detection signal generator and input to the selector. A clamping unit performs a clamping process to suppress DC level fluctuation in the playback signal based on the detection signal when the selection unit selects the detection signal, and does not perform the clamping process when the selection unit selects the null signal. A signal processor performs specific signal processes based on clamping unit output.

Optical disc device

A recording/producing device for writing data on a recording medium, or reading data from the recording medium, wherein data matching a recording pattern so specified as to include a plurality of mutually different sets of mark lengths and space lengths is written on the recording medium, and the data is then read to generate data signals. An edge shift detector uses data signals to measure the edge shift amount of a mark formed on a recording medium for each set of a mark length and a space length. A record controller sets a recording parameter for each set of a mark length and a space length based on the measured edge shift amount.

Recording/reproducing device

A laser power control method according to the present invention is a method for controlling an output power of a laserwhich is used for recording information on a recording medium. The method comprises steps of: detecting emitted light of the laser by a first detection section; obtaining a first driving current of the laser by a first control sectionbased on an output of the first detection section; detecting reflected light or transmitted light from the recording medium by a second detection section; and obtaining a second driving current of the laser by a second control sectionbased on an output of the second detection section. The laser is driven based on the first driving current or the second driving current while the first control section and the second control section are operated alternately such that the second control section does not operate when the first control section is operating, and the first control section does not operate when the second control section is operating. With such a structure, even when a plurality of laser powers which are switched at a high speed are required for recording of information, each laser power can be controlled so as to be an appropriate power for recording of information.

Laser power control method and optical disk device

A semiconductor laser driving apparatus for directing light to an optical disc for recording a recording mark based on a recording current and reproducing the recording mark to generate a reproduction signal. The apparatus includes a reproduction current generation section; a high frequency current generation section for generating a current including a high frequency component for reducing semiconductor laser noise in the reproduction; a recording current generation section, the recording current including a pulse corresponding to the recording mark and including a plurality of multi-pulses; and a current driving section for amplification. The apparatus further includes a filter to attenuate the enhanced high frequency components in the high frequency current and in the enhanced high frequency component; and a switching section for switching the filter so that the enhanced component in the recording current is superposed on at least one of the multi-pulses.

Semiconductor laser driving apparatus with filter to attenuate enhanced frequency component and optical disk apparatus including the same

The laser drive device of this invention includes a laser, first and second current sources, a current amplifier, and first and second transistors. When the first transistor is OFF, a first current from the first current source is supplied to the current amplifier, where the current is amplified to generate a laser current to be supplied to the laser. Thus, the laser is turned ON. During this time, the second transistor is ON, allowing a second current to flow from a power supply node into the second current source. When the first transistor is ON, the entire or part of the first current flows into the second current source through the first transistor. This reduces the current supplied to the current amplifier and thus the laser current, resulting in turning OFF the laser. During this time, the second transistor is OFF. The values of the first and second currents are determined by a set current value. The value of the laser current supplied to the laser during the ON-state of it is determined by the first current. Therefore, by adjusting the set current value, a desired value of laser current can be supplied to the laser. Having the current amplifier, the values of the first and second currents are smaller than the value of the laser current. This suppresses an increase in power consumed by the first and second power sources and the first and second transistors when the laser current increases.

Laser drive device

A laser power controller detects the temperature and current setting used for the recording power during initial learning or the previous recording operation. When a new recording operation starts, the controller detects the temperature again and compared the detected temperature with the temperature at initial learning or the previous recording to adjust the current setting used for the previous recording power setting and set the initial recording power current of the new recording operation.

Apparatus and method of controlling laser power

The invention provides an optical disc device and a method of determining an optimal laser power for data recording by trial recording before recording actual user data even when there are fingerprints in the test track area for the trial recording. The BER (Byte Error Rate) is detected in each recorded sector. If the BER is less than a particular threshold value, the sector is taken as OK (good). Otherwise the sector is taken as NG (no good). While the peak power level is gradually changed or decreased from the power level at which half or more of the plural reproduced sectors are OK, a boundary peak power at which half or more of the sectors become NG is found. Based on the found boundary power, an amount of the optimal peak power is determined.

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Osaka, Japan

Toshiya Akagi