Sanyo Electric Co., Ltd.

Other

Hitachi Maxell, Limited

Sanyo Electric., Ltd.

Satoshi Sumi

Atsushi Yamaguchi

Kenji Nakao

Kenji Tanase

Yoshihisa Suzuki

Noboru Mamiya

Yoshiharu Uchihara

Yoshihiro Hori

Kenji Torazawa

Hisashi Matsuyama

Toshiaki Hioki

Kenji Asano

Hitoshi Watanabe

Norio Ohta

Hiroyuki Awano

Naoyuki Takagi

Ken Hirose

Hiroshi Shirai

Seiji Murata

Morio Nakatani

Seiichiro Takahashi

Akiomi Kunisa

Nobuo Itoh

Takeshi Maeda

Shigemi Maeda

Tetsu Watanabe

Katsusuke Shimazaki

Hiroshi Watanabe

Yoichi Tsuchiya

Masaaki Kurebayashi

Masafumi Yoshihiro

Yasuhito Tanaka

Nobuhide Matsubayashi

Toshihide Hamaguchi

Shigekazu Minechika

Masahiro Nakata

Masami Makino

Sayoko Tanaka

Shigeki Hori

Michio Matsuura

Hideharu Toda

Sayoko Okada

Tomohiro Goto

Nobuyuki Nagai

Satoru Oonuki

Kenji Torasawa

Koichi Kawakami

An information recording and reproducing apparatus for increasing a speed of tilt control, including a portion for storing reference data, a portion for storing sample values data, a portion for obtaining positional information, a stilt servo generator, a tilt adjuster.

Information recording and reproducing apparatus

The present invention aims to smoothly and adequately adjust recording laser power while an increase in processing load during recording is suppressed. When a recording operation start request is received, OPC is executed with reference to a target &#x3b2; value (&#x3b2;t) of a disc to set recording laser power Pws. Recording operation is performed based on the set recording laser power Pws. When a system is brought into an intermittent standby state, R-OPC is executed, so the recording laser power Pws is adjusted and set again. Then, its subsequent recording operation is performed based on the recording laser power Pws which is set again. When a duration of the recording operation exceeds a maximal waiting time Ts, the recording operation is suspended so that the system is set to a recording standby state. Then, the R-OPC is executed, so that the recording laser power Pws is adjusted and set again.

Optical disc device for recording and reproducing information on and from a write-once-type disc using laser light

A substrate in which a minute ruggedness structure including columnar projections is formed in a track shape is prepared. The pitch of the columnar projections of the ruggedness structure is set such that a plurality of the columnar projections is within a beam spot. A flat portion is disposed between adjacent tracks. A reflecting layer is formed on the substrate. The flat portion becomes a mirror surface because of the formation of the reflecting layer. The reflectance of the ruggedness structure becomes significantly lower than the reflectance of the flat portion. When the ruggedness structure is irradiated with high-power laser light, a portion of the ruggedness structure is raised to a reflecting layer side and flattened. At this time, reflectance of the raised portion becomes higher than reflectance of a non-raised portion. When a track including the ruggedness structure is irradiated with high-power pulse laser light, signal recording based on a change in reflectance is possible.

Optical recording medium, optical recording method, optical reproducing method, optical recording apparatus, and optical reproducing apparatus

A layered magneto-optical recording medium including a substrate and a magnetic layer. The magnetic layer includes columnar projections, which are formed on a film surface of the magnetic layer as arranged in a lengthwise direction and a crosswise direction with a pitch smaller than a wavelength of the laser light.

Magneto-optical recording medium and layer structure

Provided is an optical disc device in which adjustment precision of recording laser power is improved without complication of a processing sequence during recording operation. In response to a recording start instruction, OPC is executed using an inner disc drive zone to set an initial value of recording laser power Pws. Then, when a first recording instruction REC(1) is detected, recording is successively performed from the head of a data area using the laser power Pws. After that, when an intermittent standby period is set, sample data is recorded to a next recording position and R-OPC is executed. Therefore, the recording laser power Pws is set again. Next, when a second recording instruction REC(2) is detected, recording is successively performed from a next recording position, that is, a position next to an end portion of the first recording instruction REC(1) using the reset laser power Pws. At this time, data corresponding to a head portion of the second recording instruction REC(2) is overwritten on sample data in the head of the recording position.

Optical disc device

Provided is an optical disc device in which adjustment precision of recording laser power is improved without complication of a processing sequence during recording operation. In response to a recording start instruction, OPC is executed using an inner disc drive zone to set an initial value of recording laser power Pws. Then, when a recording instruction REC() is issued, recording is successively performed from the head of a data area using the laser power Pws. After that, when an intermittent standby period T is set, sample data is recorded at the number of times corresponding to the intermittent standby period T in a next recording position, and R-OPC is executed. Therefore, the recording laser power Pws is set again. Then, when a second recording instruction REC() is issued, recording is successively performed from a next recording position, that is, a position next to an end portion of data recorded by the first recording instruction REC() using the reset laser power Pws. At this time, data corresponding to a head portion of the second recording instruction REC() is overwritten on sample data in the head of the recording position.

A magneto-optical disk apparatus generates magnetic field onto a magneto-optical recording medium prior to recording signals in the magneto-optical recording medium having a recording layer and a reproduction layer, by use of magnetic field and laser beam. The magneto-optical apparatus then adjusts a position of a magnetic head that generates the magnetic field, under a state where the laser beam is irradiated, by utilizing that an irradiation spot of the laser beam deviates due to eccentricity of the magneto-optical recording medium. This position adjustment is carried out based on, for example, a beam position signal showing the irradiation spot of the laser beam and/or a detection signal which is detected after the laser beam is modulated by the magnetic field.

Magneto-optical recording apparatus capable of adjusting the magnetic head

A magneto-optical recording medium which includes a reproducing layer. When a laser beam is irradiated to the magneto-optical recording medium, a magnetic domain in a recording layer is transferred, through enlargement, to a reproducing layer increased in temperature. The magneto-optical recording medium further includes a calibration area that has a calibration magnetic domain recorded in a predetermined pattern in the recording layer. In a reproducing apparatus, a laser beam of an optical head is adjusted in output depending upon a reproduced signal obtained by reproducing the calibration magnetic domain.

Magneto-optical recording medium including a calibration magnetic domain recorded in a predetermined pattern in a recording layer

A magneto-optical record medium and a reproducing apparatus for the same allow data reproduction having good characteristics by a simple structure. The magneto-optical record medium includes a plurality of first grooves ( ) each having sidewalls, at least one of which is wobbled in accordance with address information; an address mark ( ) formed by changing a width of a land located between second grooves connected to the first grooves; and third grooves wobbled cyclically, formed in a data portion magnetically storing data and connected to the second grooves. The reproducing apparatus reproduces the data from the magneto-optical record medium.

Record medium and reproducing apparatus of the same for detecting an offset correction

The present invention provides a recording medium and an information recording/reproducing apparatus which permit recording and/or reproducing by a laser beam of optimized power for each recording medium. The recording medium is provided with a calibration region in addition to an information recording region. The calibration region has wobbles formed such that the amplitude of the waveform of a reproduced signal therefrom can change. Prior to recording to the information recording region, a signal is recorded in the calibration region by changing the laser power, and the recorded signal is immediately reproduced. The waveform of the reproduced signal is evaluated to determine optimum laser power for recording. At the time of reproducing, a signal previously recorded in the calibration region is reproduced while changing the laser power, and laser power optimum for reproducing is determined.

Information recording/reproducing apparatus

A magneto-optical recording medium has, in order from the laser irradiation side, a second auxiliary magnetic film first auxiliary magnetic film and magneto-optical recording film First and second auxiliary magnetic films and change from in-plane magnetization to perpendicular magnetization when their respective critical temperatures T and T are exceeded. The Curie temperatures T , T and T of the magneto-optical recording film and the first and the second auxiliary magnetic films and their critical temperatures T and T satisfy the relationship: room temperature<T <T <T , T ,T . The first auxiliary magnetic layer has a film thickness greater than the thickness of the magnetic wall. In response to irradiation by the reproducing light beam, recording magnetic domain of magneto-optical recording film is transferred, with size reduction, to first auxiliary magnetic film and is then transferred, with magnification, to second auxiliary magnetic film This is ideal for reproduction of a high-density recording medium since an amplified reproduction signal is obtained from magnified magnetic domains

Magneto-optical recording media having an auxiliary magnetic layer

An magneto-optical disc recording/reproducing apparatus includes an optical head ( ) to detect a wobble ( ) and an address mark ( to ) in an magneto-optical disc ( ) and output a wobble signal (WB , WB ) and an address mark signal (AML, AMG), a PLL circuit ( ) to generate a clock signal (CK) in response to wobble signal (WB ), an address mark synchronous signal generation circuit ( ) to generate an address mark synchronous signal (AM) in response to address mark signal (AML, AMG), a synchronizing circuit ( ) to synchronize clock signal (CK) with address mark synchronous signal (AM) and generate a synchronized clock signal (SCK), and a timing setting circuit ( ) to generate a timing pulse signal (TG ) to control a magnetic head driving circuit ( ) and a timing pulse signal (TG ) to control a laser driving circuit ( ). The recording/reproducing apparatus can detect a address mark ( to ), record la data signal on magneto-optical disc ( ) in synchronization with the detected address mark, and reproduce a data signal from magneto-optical disc ( ) in synchronization with the detected address mark, so that the data signal can be surely recorded/reproduced.

Information recording/reproducing apparatus to record/reproduce information on a recording medium recorded with an address mark

An optical pickup device for an AS-MO disk, a DVD and a CD includes a dual wavelength semiconductor laser with first and second oscillation devices, a polarization plane rotary unit selectively rotating a plane of polarization of a laser beam 90&deg;, and a polarization selective diffraction grating passing a laser beam straight forward or dividing a laser beam into three beams depending upon the direction of polarization. The optical pickup device operates by the DPP tracking system where three laser beams are directed for an AS-MO disk, and by the DPD tracking system where a single laser beam is directed for a DVD or a CD. As a result, a signal can be reproduced from an AS-MO disk, a DVD, or a CD having different tracking systems.

Optical pickup device having compatibility with tracking system, and optical disk recording/reproduction apparatus using the same

An information recording and reproduction apparatus for a magneto-optical medium includes a synchronizing signal generation circuit for generating a synchronizing signal to provide a pulsed laser beam at the time of reproduction according to an internal clock obtained from a reproduction signal. The laser beam is driven on/off according to the synchronizing signal at the time of reproduction to have the laser spot on the signal plane prevented from being enlarged, so that the reproducible domain is smaller than the domain of when a laser beam is continuously emitted. In reproduction, an optical superresolution method is applied simultaneous to provision of a pulsed laser beam to allow reproduction of higher density. An external synchronizing signal generation circuit for generating an external synchronizing signal according to a wobble on a surface of a recording medium can be used instead of a synchronizing signal generation circuit according to an internal clock.

Information recording and reproduction apparatus carrying out recording and reproduction of information using laser beam

A meandering groove is formed in a digital disk (,) with a wobble signal that is wobbled to reproduce a clock signal. The wobble signal is read out by an optical head (,). An address detection circuit (,) detects an address signal that is multiplexed with the wobble signal. A PLL oscillation circuit (,) provides a clock signal in synchronization with the wobble signal. Data is modulated by a modulation circuit (,) according to the clock signal and a timing signal based on the address signal, and recorded on the digital disk (,). In reproduction, a RF signal in the wobble signal is converted into a digital signal by an A/D converter (,). The signal is demodulated by a demodulation circuit (,) for data output.

Digital disk recording and reproduction apparatus

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Gifu, Japan

Satoshi Sumi