Hitachi, Ltd.

Hitachi-lg Data Storage, Inc.

Hitachi Maxwell, Ltd.

Tsuyoshi Toda

Takeshi Maeda

Makoto Miyamoto

Keikichi Andoo

Motoyasu Terao

Akemi Hirotsune

Hideki Saga

Yumiko Anzai

Tetsuya Nishida

Junko Ushiyama

Masatoshi Ohtake

Toshimitsu Kaku

Hiroyuki Minemura

Fumiyoshi Kirino

Hiroshi Ide

Atsushi Saito

Kazuo Shigematsu

Shigeru Nakamura

Seiichi Mita

Koichiro Nishimura

Hiroyuki Tsuchinaga

Mitsuhide Miyamoto

Yasushi Miyauchi

Hidehiko Kando

Fumio Kugiya

Masaaki Kurebayashi

Toshiki Ishii

Toru Kawashima

Atsushi Yamada

Shigeki Yamazaki

Hisataka Sugiyama

Yasuhide Ouchi

Nobuhiro Takeda

Takakiyo Yasukawa

Mitsuru Harai

Harukazu Miyamoto

Yoshio Suzuki

Kimio Tatsuno

Masahiro Ojima

Hiroyuki Awano

Toshio Niihara

Kiyoshi Matsumoto

Takeyoshi Kataoka

Yasushi Fukuda

Tooru Kawashima

Masahiko Ishimaru

Tomoya Hoshi

Mitsuhiro Nishidate

Takuya Himi

Sadatsugi Machida

Michael McLoughlin

Horishi Ide

Recording parameters are decided so that the time control information on at least the front edge and the rear edge of a parameter forming a mark of twice size or above of the laser spot diameter focused on the recording medium is substantially proportional to the recording linear velocity. The mark is recorded and reproduced at a predetermined linear velocity to obtain an electric signal waveform having a time width Tm. A parameter is decided so as to control the laser pulse for recording information so that a voltage value change amount at two points at a distance Ts (Ts&#x3c;Tm/2) in the time axis direction before and after the time position Tm/2 from the front edge of the waveform is substantially constant for the recording linear velocity change. Identification information indicating the parameter is described on the recording medium.

Recording medium, optical disk apparatus and writing method

In a recording/reproducing apparatus and a recording method, for enabling a high reliability on reproduction data are conducted the followings: recording a test mark within the test aria with a predetermined write strategy; obtaining signal amplitudes corresponding to a front portion, a middle portion, and a rear portion of the test mark, by reproducing the test mark; determining on whether the test mark has a desirable configuration or not, upon basis of at least one of ratios, defined between the amplitude of the front portion and the amplitude of the rear portion, and between the amplitude of the middle portion and the amplitude of the rear portion; correcting the write strategy if it is determined that the test mark has not the desirable configuration; and recording the information within the data area with the write strategy after the correction thereof.

Optical disc recording apparatus and optical disc recording method

It is to provide an optical disc recording apparatus and a recording power control method that are adapted to high-speed recording and can set an optimal erasing power with high accuracy. A test writing signal detector reproduces a test writing signal of a predetermined mark length or space length with varied power, and detects the number of error mark signals and an amplitude value of an envelope. A controller obtains a first threshold Peof the erasing power based on the number of error mark signals in a region where laser power is low, and obtains a second threshold Peof the erasing power based on the amplitude value in a region where the laser power is high. Then, the controller sets an optimal value of the erasing power from an average value of the first and second thresholds.

Optical disc recording apparatus and recording power control method

Pulses modulated between the erase power and the bottom power are used instead of cooling pulses for an optical disk medium that needs a write strategy with 4-valued power levels. Consequently, pulse instruction lines for the cooling pulses, power level instruction lines, and corresponding current source within the laser driver can be omitted. Decrease in size and lower power consumption can be accomplished.

Multiple pulse recording method with 3-valued power levels

Test writing is executed while skipping areas where deviations are present on an optical disk to thereby improve accuracy and reliability of an optimum recording condition to be derived. A deviation detecting unit detects the deviations of a guide groove on the optical disk on the basis of a fluctuation amount of a focus error signal or a tracking error signal, and registers information of the detected deviations onto a memory. A test writing processing unit refers to the memory, and records and reproduces a test signal while skipping the areas where the deviations are detected.

Optical disk apparatus and test writing method

Provided is an optical disk device capable of recording and/or reproducing information on optical disks with high reliability; and a method for controlling the optical disk device. The position of an optical lens where the amplitude of a reproduction signal during the period corresponding to a minimum-length recording mark and a space having the same length reaches its maximum is detected; and the detected position is set as a reference position for the objective lens relative to the optical disk, for use in focus control. Also, the position of the objective lens where the result of multiplication of resolution and modulation becomes greatest is detected; and the detected position is set as a reference position for the objective lens relative to the optical disk, for use in focus control.

Optical disk device and control method for the same

Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Information recording method and apparatus with suppressed mark edge jitters

For achieving pulling operation into tracking servo during seek operation at high-speed and with stability, in timing thereof, even on an optical disk forming lands and grooves on a recording surface thereof, in a seek control method, according to the present invention, for moving an optical spot onto an arbitrary track through movement of an optical pickupinto the radial direction on the optical disk forming the lands and the grooves, thereby forming a track on the recording surface thereof, in particular, in the seek operation, measurement is made on a period of a tracking error (TE) signal generated due to the movement in the radial direction, and a time point when the measured period of the tracking error signal exceeds a predetermined value is determined to be a starting point for pulling the optical spot of the optical pickup into the track, through the tracking servo, thereby pulling it selectively, into either one of the land and the groove building up the track.

Optical disk recording/reproducing apparatus and seek control method thereof

In the present invention, the processing sequence of a microprocessor for restructuring the recording parameters when changing the recording in an optical disk recording apparatus from a constant angular velocity (CAV) mode to a constant linear velocity (CLV) mode is as follows: (1) interrupt the recording process; (2) calculate a linear velocity at a point where the recording linear velocity becomes constant; (3) calculate a third recording parameter in the linear velocity by a linear interpolation based on first and second recording parameters which are corrected by test writing, replacing all the recording parameters for an outer circumference of an optical disk from a radius position where the linear velocity becomes Cx, with the third recording parameter; and (4) restart the recording with the third recording parameter as a recording condition.

Recording control method for optical disk recording apparatus and optical disk recording apparatus

Means is provided that produces stabilized trial write results when, for example, servo misalignments are caused due to deviations on an optical disc that requires trial writes at high linear velocity. A recording method produces a recording parameter in the event of recording information into an arbitrary address position in the manner that a recording parameter is obtained through a predetermined calculation method from the results of learning of recording parameters on two or more zones of the optical disc where the linear velocities are different form one another. In a zone where the linear velocity is low, the method determines an optimal recording parameter from a jitter value of a reproduced signal waveform generated in a trial write. In a zone where the linear velocity is high, the method determines an optimal recording parameter in accordance with information obtainable from an amplitude value of a reproduced signal generated in a trial write.

Optical information recording method and optical information recording apparatus

An optical disc apparatus, as a learning operation before a recording or reproducing operation, rotates an optical disc at a first speed to read PID information, discriminates between lands and grooves of the optical disc, detects switching positions between lands and grooves, sets a rotation angle position of tracking pull-in of an objective lens of a time length that allows the PID information to be stably read, with respect to the switching position, and stores the set position information of tracking pull-in as learning result information. During recording or reproducing, the optical disc apparatus rotates the optical disk at a second speed higher than the first speed, pulls in the objective lens for tracking based on the stored position information of tracking pull-in, reads PID information, and performs the recording or reproducing operation while discriminating between lands and grooves and detecting switching positions between lands and grooves.

Optical disc apparatus and access control method of the same

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Kodaira, Japan

Tsuyoshi Toda