Kabushiki Kaisha Toshiba

Nec Corporation

Hiroharu Satoh

Chosaku Noda

Sadanari Fujimoto

Hisashi Yamada

Yutaka Yamanaka

Hideaki Ohsawa

Koichi Hirayama

Hiromichi Kobori

Kinji Kayanuma

Hideo Ando

Hiroaki Unno

Akihito Ogawa

Masatsugu Ogawa

Ryuichi Katayama

Toshihiro Sugaya

Koji Maruyama

Seigo Ito

Toyoki Taguchi

Teruo Murakami

Isao Hoshino

Masahiko Tanaka

Naobumi Seo

Kei Shimura

Junichi Uota

Takeharu Shibatoko

Daisuke Eto

The length of a format modulation area in an address segment is limited to be 25% of the address-segment length or less, and the position of the format modulation area is selectable two possible positions. Subsequently, where a CLV optical-disk medium is used, wobble modulation areas in adjacent recording tracks do not overlap each other in the radius direction.

Optical disk medium and optical disk apparatus

There is provided an information management apparatus which can make it impossible to read out data recorded on a write-once type recordable optical disk as required and the usefulness thereof is enhanced. When recorded data is destroyed on the write-once type recordable optical disk, data modulated by a modulation system of the same run length restriction as run length restriction of a modulation system used for recording data is overwritten and recorded, data is overwritten and recorded by use of patterns in which the frequency of occurrence of spaces of the longest code is higher than the frequency of occurrence of the modulation system used for recording data, or data is overwritten and recorded by use of successive patterns of the shortest code in the run length restriction of the modulation system used for recording data.

Information recording medium, information recording/reproducing apparatus and information management method

In an optical disk medium, land recording tracks () are coupled by first and second coupling portions (and) at a particular radial position to form a tilt detecting mark SM.

Optical disk medium and optical disk recording/reproducing apparatus utilizing tilt detection areas having special marks

According to this invention, general addresses are given to a multi-layer information storage medium to facilitate handing of information. That is, it is possible to set generalized addresses for multiple information layers, and information indicating a condition for setting the general addresses, e.g., the contents of a disk ID zone in a rewritable zone of a lead-in area, is recorded on an information reproducing layer.

Multi-body multi-purpose information processing apparatus

Pits and lands which have a pit length of 3T, a land length of *6T, a pit length of 7T, a land length of *3T, a pit length of 6T and a land length of *7T are alternately formed in a lead-in area in an inner track area on an optical disk as a test pattern for evaluating a read error of the optical disk. This test pattern data is reproduced by a reproducing system to detect an error rate, a compensation coefficient for minimizing the error rate is acquired, and a reproduction signal is compensated by using this compensation coefficient so that the reproduction signal is reproduced with the minimized error rate by the reproducing system.

Optical disk having an evaluation pattern for evaluating the optical disk

Signal processing systems can be switched according to the optical system selected from a plurality of optical systems and set to the operating state. A system controlling portion 100 finally sets an appropriate optical system according to the kind of an optical disk 11, and sets an appropriate signal processing system corresponding to the set optical system for setting an appropriate mode depending upon CD (compact disk) or DVD (high density recording disk).

Reproduction device for optical disks

An excellent waveform signal with less jitter is obtained as an output signal from a reproducing optical pickup, irrespective of a relative reading speed. Thus there is no need for an equalizing circuit on a reproducing apparatus side. An input bit sequence or a recording NRZI signal is combined with spatial frequency characteristics G(fs) by a G(fs) converter. An output signal from the G(fs) converter is combined with equalizing frequency characteristics EQ(fs) necessary on a reproducing side by an EQ(fs) converter. An output from the EQ(fs) converter is saturation-amplified by a saturation amplifier, thereby producing an ideally pre-jittered recording signal that has equivalent enhanced high-frequency component. The recording signal is recorded on an optical disk.

Method and apparatus for recording digital signals medium for recording

An excellent waveform signal with less jitter is obtained as output signal from a reproducing optical pickup, irrespective of a relative reading speed, and an equalizing circuit is dispensed with on a reproducing apparatus side. An input bit sequence or a recording NRZI signal is provided with spatial frequency characteristics G(fs) by a G(fs) converter. An output signal from the G(fs) converter is provided with equalizing frequency characteristics EQ(fs) necessary on a reproducing side by an EQ(fs) converter. An output from the EQ(fs) converter is saturation-amplified by a saturation amplifier, thereby producing an ideally pre-jittered recording signal that has equivalent enhanced high-frequency component. The recording signal is recorded on an optical disk.

Method and apparatus for recording digital signals, medium for recording

An optical disk apparatus includes a semiconductor laser for emitting a light beam, and an automatic power control or APC circuit for driving the laser. A compound prism structure is optically coupled to the laser in an optical head section, and defines a first optical path for causing a front laser light to be projected onto a rotating optical disk and guiding a reflected light therefrom toward a first photodetector, and a second optical path for guiding a part of the reflected light toward a second photodetector. An output signal of the first photodetector is used to generate a reproduced information signal. An output signal of the second photodetector is fed back to the APC circuit as a front light monitor signal. A part of a laser control signal internally generated in the APC circuit is supplied through a wiring line to a noise reduction circuit as a laser noise monitor signal. The noise reduction circuit subtracts this noise monitor signal from the reproduced information signal to provide a noise-suppressed information signal.

Noise reduction system for optical record and reproduction apparatus

Growing community of inventors

Tokyo, Japan

Hiroharu Satoh