Ricoh Company, Ltd.

Kenya Yokoi

Haruo Iimura

Naruhiro Masui

Akihiko Kanemoto

Takamichi Enomoto

Yasuyuki Takiguchi

Akihiko Shimizu

Ryosuke Kasahara

Hiroshi Koide

Michiaki Shinotsuka

Michiharu Abe

Wasaburo Ohta

Tetsuya Ogata

Sumio Kamoi

Ikuo Aoki

Kohji Takeuchi

Fuyuhiko Matsumoto

Teruyasu Watabe

Yukiko Hamano

Takaaki Miyashita

Yukiko Katoh

Toru Miyabori

A multi-layered information recording medium used in an information recording/reproducing apparatus applicable to both a single-layer information recording medium and an arbitrary multi-layered information recording medium is provided. The multi-layered information recording medium has a plurality of recording layers, and each of the recording layers has a guiding groove formed at a track pitch defined as a quadratic function of disk thickness (i.e., the distance from the light incident surface) of the associated recording layer. The guiding grooves of the recording layers are formed such that the track pitch of a reference recording layer having a disk thickness closest to that of the single-layer information recording medium is the smallest amongst the multiple recording layers.

Multilayer information recording medium, information recorder, and information reproducer

A data readout method is disclosed that is able to read data from an optical disk capable of super resolution readout with high accuracy. The data readout method allows reading data recorded in an optical disk by irradiating a laser beam onto the optical disk. The method includes the steps of varying a light emission power level of the laser beam while the laser beam is irradiated onto the optical disk, and acquiring a reflectivity of the optical disk corresponding to each light emission power level; calculating a second derivative of a curve representing correlation between the reflectivity and the light emission power with respect to the light emission power; calculating an extreme value of the second derivative; and calculating an optimum readout power level for super resolution readout based on the extreme value.

Data readout method, data readout device, and optical disk

In an information recording method and apparatus, when performing recording by using multiple pulses defined by erase powers Peand Pefor forming a space part between mark parts, the set values of the erase powers Peand Peare updated at predetermined intervals in accordance with a recording linear velocity.

Information recording apparatus that can achieve uniform signal characteristics and overwriting characteristics over an entire surface of an optical disk medium

An information recording method includes the steps of recording test data with changing a top pulse width Ton and monitoring reflected light intensity; determining an optimum top pulse width from the monitoring result; determining respective optimum off pulse widths according to multilevel data from a monitoring result of the determined optimum top pulse width; recording test data with changing recording power in sequence with the use of the optimum top pulse width and the optimum off pulse width determined, monitoring reflected light intensity, and thus determining optimum recording power.

Information recording method, information recording apparatus, optical disk, program and computer readable recording medium

A first trial write process obtains an optimum recording power of a test pattern even with respect to data having different rules for the recording waveforms corresponding n type data length sets, and a second trial write process using this optimum recording power obtains optimum pulse width or optimum pulse edge position separately for each data length set. Based on the optimum recording power and optimum recording waveform obtained by these trial write processes, recording operation is performed so as to form all the data lengths with satisfactory accuracy, thereby making it possible to obtain a proper reproduced signal.

Information recording method, information recording device, and recording medium containing a program, with recording marks formed by emitting light

Information recording method and information recording apparatus that can achieve uniform signal characteristics and overwriting characteristics over an entire surface of an optical disk medium

The present invention discloses an optical information recording method of an optical information recording and reproduction device that uses a semiconductor laser to record or reproduce data in an optical disk. Based on a detected value of an optical path difference of the optical disk, a calculated value of optimum recording power for recording data or an object value of recording power when data are being recorded is corrected. In addition, when calculating the optimum recording power before recording data in the optical disk, an optimum index (&#x3b2;) indicating the optimum recording power is corrected with respect to a predetermined first index, and the corrected optimum index is used as the calculated value of the optimum recording power Pwo. The predetermined first index is obtained by reproducing a trial write region which is recorded with recording power being varied stepwise.

Information recording method, recording optical disc, and information recording/recording/reproducing apparatus

An information recording device comprising at least a recording pulse generating means and a recording pulse selecting means capable of generating various multi-pulses each of which is a combination of a leading heating pulse and a succeeding heating pulse, and rectangular pulses each of which is a single pulse, as a recording pulse, is disclosed. The recording pulse selecting means switches and selects among the multi-pulses and the rectangular pulses according to a recording condition, and then causes a light emission of a laser light source through a light source driving means. Even though in a high recording linear velocity recording condition that is insufficient in power for the recommended multi-pulse recording, a very low recording power can still be used by switching to the rectangular pulse recording, so as to achieve a recording with a much higher recording speed. In addition, good recording marks can be formed without exceeding a maximum allowable recording power.

Information recording device

An optical information recording method and apparatus which records information on a recording medium by irradiating the recording medium with an irradiation light of a recording power to form a recorded-mark on the recording medium such that reflection coefficient from an area of the recorded-mark is different than a reflection coefficient from an area of the recording medium where the recorded-mark is not formed by a changing power of the irradiation light. Information is recorded by modulating the irradiation light according to the information for recording, forming a recorded-mark on the recording medium by changing the power of the irradiation light between a recording power and a non-recording power, receiving reflection light of the irradiation light reflected by the recording medium and producing a corresponding light signal, determining a state of the recorded-mark based upon the light signal produced during a predetermined period of time immediately after the irradiation light changes from the recording power to the non-recording power, and controlling the recording power of the irradiation light according to the state of the recorded-mark.

Optical information recording method and apparatus

An optical information recording medium and a method of mastering an optical information recording medium. Cross-talk is avoided even when phase pits flanking a groove are radially aligned so that preformat information can be reliably reproduced after information is recorded at the grooves. A phase pit that encodes preformat information for a groove is radially spaced from that groove by a partition wall but is connected to an adjacent groove. When mastering, respective first and second exposing light beams are used to form the grooves and the phase pits, and the spacing between the two beams and, therefore, the width of the partition walls in the radial direction is precisely and easily controlled by controlling the inclination angle of at least one of the beams relative to an objective lens in the mastering exposure system.

Optical information recording medium with a partition wall between an information tracks groove and a preformat pit encoding information therefor

A disk apparatus performs optical recording onto an optical disk with a record mark by using a light beam modulated in a manner of multi-pulse series, includes. A detection pulse generating part generates a detection pulse to replace the multi-pulse series; and a detection power control part controls the power of the detection pulse to be smaller than the power of the multi-pulse series.

Optical information recording employing improved recording power control scheme

An input bit sequence with predetermined bit periods T is converted into a corresponding light-emission waveform; and a beam with the thus-obtained light-emission waveform is applied onto a phase-change optical disk so as to record the input bit sequence thereon. The light-emission waveform comprises a heating pulse for heating the recording medium occurring for an interval tw and a cooling pulse for cooling the recording medium occurring for an interval tc, and the intervals tw and tc on the heating/cooling pulses satisfy the following requirement in case the heating/cooling pulses occur alternately with repetition: 1.5T&lE;tw&plus;tc&lE;3T.

Information recording with effective pulse control scheme

An information recording method records information on an optical disk by a recording pulse signal of an optical beam that is emitted from an optical source. A recording channel clock period T is changed depending on a change of a recording linear velocity so that a recording linear density is maintained approximately constant. In addition, a shape of a pulse waveform of a top heating portion of the recording pulse signal which includes a rear heating portion, is changed at predetermined intervals depending on a desired recording linear velocity, so that a width of the top heating portion and a recording power thereof are changed.

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Kanagawa, Japan

Kenya Yokoi