Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Matshushita Electric Industrial Co., Ltd.

Takeharu Yamamoto

Katsuya Watanabe

Takashi Kishimoto

Kenji Fujiune

Mitsurou Moriya

Yoshihiro Kanda

Shin-ichi Yamada

Hiromichi Ishibashi

Kenji Kondo

Yasuaki Edahiro

Jun Kikuchi

Yuichi Kuze

Toshio Matsumoto

Hiroyuki Yamaguchi

Mitsuro Moriya

Akihiro Arai

Takeshi Shimamoto

Shinichi Yamada

Rie Takahashi

Hisashi Senga

Yuu Okada

Toshiaki Takasu

Kazushi Andoh

Kouichi Ikeuchi

Yoshiaki Komma

Yasumori Hino

Kousei Sano

Makoto Usui

Shinji Inoue

Yuji Takagi

Hidenori Wada

Masaru Yamaoka

Hideki Nakata

Yoshihisa Takahashi

Osamu Mizuno

Hideki Aikoh

Joji Anzai

Yuuichi Kuze

Keisuke Fujimoto

Kenzo Ishibashi

Tetsuya Shihara

Katsuhiko Yasuda

Minoru Takazawa

Akinori Yuba

Tatsuya Takeuchi

Yoshirou Kashiwabara

Yasuo Ooishi

An information recording apparatus includes: a first memory which stores synchronization data for updating data on a recordable optical disc and/or adding data to the recordable optical disc; a second memory which stores erasure information indicating data to be erased; and a controller which controls addition, update, and erasure of data on the optical disc. The controller records the synchronization data onto the optical disc. After recording the synchronization data, the controller records, onto the optical disc, management information indicating the state of the optical disc on which the synchronization data has been recorded and the state of the optical disc resulting from erasure according to the erasure information. Subsequently, the controller closes the session. After closing the session, the controller physically erases the data to be erased which has been recorded on the optical disc.

Apparatus and method for recording and erasing user data on a recordable optical disc

A data erasing method of the present disclosure is a data erasing method for erasing data stripe-recorded in a plurality of write-once optical discs constituting a redundant arrays of inexpensive disks (RAID) system and each including a plurality of data recording blocks and a redundant data block. In the data erasing method, alternate recording of at least one target block and the redundant data block is performed in a predetermined alternate area. The target block is one of the data recording blocks in which target data as erase target data is recorded. The target block is overwritten such that the target data is not correctly read.

Data erasing method

With a large capacity of an optical disk and high-speed recording, a frequency of a recording signal is increased and a pulse width is narrowed. In the case that a laser is driven by a signal having the short pulse width, unfortunately the high-speed recording is hardly performed to an optical disk when a rise time and a fall time of the optical pulse are lengthened. During user data recording, a bottom driving current is set to a second bottom driving current value that is a current value of a threshold or less, so that the rise time and the fall time of the optical pulse can be shortened to perform the high-speed recording of the optical disk.

Laser power control method and laser power control apparatus

Provided is an optical disk apparatus capable achieving stable focus control or tracking control. A first detector receives reflected light from an object lens optical system, a second detector receives reflected light from a prescribed information layer, a positional deviation determination unit determines positional deviation between a focal point of a light beam and a point where information on the prescribed information layer is recorded or reproduced, on the basis of a signal from the second detector, a stray light determination unit determines a surface stray light component which is reflected light from the surface of an optical disk and is included in the signal from the positional deviation determination unit, on the basis of the signal from the first detector, and a stray light correction unit corrects the signal output from the positional deviation determination unit on the basis of the surface stray light component thus determined.

Optical disk apparatus

An optical disc apparatus has: a spherical aberration correction unit () which corrects the spherical aberration generated in a light spot on a recording layer; a control unit () which focuses a light beam on a predetermined recording layer, and shifts the focal point position of the light beam from the current recording layer to another recording layer; and a focus jump control unit () which controls correction of spherical aberration and shift of the focal point position based on the interlayer distance between the current recording layer and a recording layer which adjoins in a direction opposite to a direction of shifting the focal point position of the light beam. By this configuration, focus jump is stably executed.

Optical disc apparatus, focus control method and integrated circuit

When information is recorded or reproduced on or from an optical information medium having three or more recording layers using blue light, interference by another layer light is reduced and, when information is reproduced from an optical information medium using red light, an S/N ratio is held excellently high. An optical head device includes a first laser light source () which emits blue light, a second laser light source () which emits red light, an objective lens () which focuses the blue light onto a recording layer of a first optical disc () or focuses the red light onto a recording layer of a second optical disc (), a photodetector () which receives the blue light reflected by the recording layer of the first optical disc () or the red light reflected by the recording layer of the second optical disc () and outputs an electric signal in accordance with an amount of the received blue light or red light, and a wavelength selective light blocking region () which blocks a predetermined range of the blue light including an optical axis thereof to prevent the predetermined range from reaching the photodetector (), and transmits the red light.

Optical head device, optical information device, and information processing device

An optical disc recording apparatus () is provided with a tracking servo () for tracking a spiral track of concave and convex marks, an analog signal processor () for extracting a reproduction signal corresponding to the concave and convex marks, a digital signal processor () for extracting a channel clock synchronized with a channel bit length of the concave and convex marks, and a sub-information recording section () for recording sub-information by irradiating laser light based on the tracking to the spiral track. The sub-information recording section () records all the sub-information by repeating a process of recording a part of the sub-information by discretely irradiating laser light at a specified interval and with a specified frequency in synchronism with a channel clock by one tracking to form recordable marks on a reflective film a plurality of times. By this construction, a tracking control to the concave and convex marks can be stably executed and the sub-information can be stably recorded.

Optical disc recording apparatus, optical disc recording circuit and optical disc

When a focus error signal (FE signal) is detected with an astigmatic method, a track crossing component leaks into the FE signal. Another detection method for the FE signal would reduce the leaking signal, but is not applicable when the light use efficiency decreases. An optical crosstalk correction amount determination unit () determines a correction amount to correct an output of a tracking error detection unit () based on optical crosstalk from a TE signal to an FE signal occurring in reflection light from an optical disc () when a spot crosses a track. An output of the tracking error detection unit () is multiplied by the determined correction amount, and added to an output of the focus error detection unit (). A focus control unit () executes focus control based on the addition result. This effectively reduces a TE signal component that leaks into the FE signal due to optical crosstalk.

Optical disc apparatus, crosstalk correction method and integrated circuit

An object of this invention is to improve stability of tracking control and improve recording and reproduction performance. The tracking control device comprises a main push-pull signal generation section, which generates a main push-pull signal based on a signal obtained by photoelectric conversion of return light of the main beam; a microcomputer, which detects an other-layer stray light signal component included in a signal obtained by photoelectric conversion of return light of the sub-beam; a signal correction section, which corrects the signal obtained by photoelectric conversion of the return light of the sub-beam, based on the other-layer stray light signal component; and a sub-push-pull signal generation section, which generates a sub-push-pull signal based on the corrected signal obtained by photoelectric conversion of the return light of the sub-beam.

Tracking control device, tracking control method, and optical disc device

The invention provides a tracking control device, a tracking control method, and an optical disc apparatus that enable to stably perform the tracking control, and reduce an influence of stray light from the other layer on the tracking control. A sub push-pull signal correcting section corrects a sub push-pull signal to be generated from returning light of a sub beam in such a manner that a track crossing component of a main push-pull signal to be generated from returning light of a main beam, and a track crossing component of the sub push-pull signal to be generated from the returning light of the sub beam are canceled. A low pass filter reduces a high frequency component of the sub push-pull signal corrected by the sub push-pull signal correcting section. A subtractor subtracts a sub push-pull signal passing the low pass filter from the main push-pull signal to thereby generate a tracking error signal.

Tracking control device, tracking control method, and optical disc apparatus

The output voltage of a cathode drive-type semiconductor laser driving circuit is set to a minimum, power consumption by a driving circuit portion is suppressed, and the heat that is generated by the optical head or the optical disc device is reduced. In addition to a conventional configuration, the semiconductor laser driving circuit of the invention measures the cathode voltage (Vout) of a semiconductor laser () and controls the anode voltage (Vld) such that the cathode voltage (Vout) becomes a predetermined level, and by doing so sets the output voltage of the semiconductor laser driving circuit to a predetermined level in order to curtail power consumption by the driving circuit and minimize the rise in temperature of the optical head or the optical disc device.

Semiconductor laser driving circuit, and optical disc device and integrated circuit provided with semiconductor laser driving circuit

An optical disc drive includes: an optical branching element for splitting light from a light source into main and sub-beams; a condenser element for condensing the main and sub-beams; a photodetector section including photodetectors to receive reflected portions of the main and sub-beams, each photodetector having photosensitive areas, each of which outputs a signal representing the intensity of light received there; and a computing section for generating a first focus signal, representing where the focal point of the main beam is located with respect to the storage layer, based on the reflected light of the main beam, and a second focus signal based on the reflected light of the main and sub-beams.

Optical disk unit

An optical disc apparatus includes: a converging section for converging a light beam and irradiating a rotating information medium with the converged light beam; a moving section for moving the converging section, thereby moving a converging point of the converged light beam in a direction perpendicular to an information surface of the information medium; a converging state detection section for generating a focus servo signal which represents a converging state of the light beam on the information medium based on reflected light or transmitted light of the light beam from the information medium; a focus servo control section for controlling the moving section based on the focus servo signal, so that the light beam reaches a predetermined converging state on the information medium; and a focus pull-in section for turning ON the control by the focus servo control section, wherein the focus pull-in section turns ON the control by the focus servo control section in a case where the focus pull-in section determines that the converging point of the light beam is located in the vicinity of the minimum velocity position on the information medium axial deviation.

Optical disc apparatus

An optical information apparatus includes a laser which emits a light beam, an objective lens and the like which converge a light beam emitted from the laser on an optical recording medium, spherical aberration correction instrument which is arranged on an optical axis of the light beam which links the laser and the objective lens, and corrects a spherical aberration generated on the optical recording medium. Correction is performed so that outgoing power of the laser changes according to a correction amount by the spherical aberration correction instrument.

Light information apparatus and control method of light information apparatus

An optical disk apparatus comprises a focusing means for focusing a light beam on a recording medium having first and second information faces; means for moving a focal point of the light beam in a direction substantially perpendicular to the information faces of the recording medium; means for detecting a reflected light from the recording medium; means for detecting a focus condition of the light beam on the basis on an output signal from the reflected light detecting means; a focus control means for driving the focal point moving means on the basis of an output signal from the focus condition detecting means, and controlling the light beam so that the focus condition of the light beam becomes a prescribed focus condition; and a focus jumping means for moving the focal point of the light beam from the first information face to the second information face by driving the focal point moving means.

Growing community of inventors

Osaka, Japan

Takeharu Yamamoto