Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Masahito Nakao

Shigeru Furumiya

Hiromichi Ishibashi

Junichi Minamino

Yoshiaki Komma

Yasumori Hino

Kousei Sano

Fumitomo Yamasaki

Kenji Kondo

Hidenori Wada

Harumitsu Miyashita

Hideki Nakata

Yoshihisa Takahashi

Naohiro Kimura

An information recording and reproducing device has a recording section, a reproducing section, and a deterioration detection processor which detects deterioration of a signal quality of information recorded in a recording medium. The deterioration detection processor reproduces information recorded in a first area of the medium, using the reproducing section, to acquire first comparison information representing a signal quality, records information, using the recording section, in a second area of the medium different from the first area after the information recorded in the first area is recorded in the first area, and reproduces, using the reproducing section, the information recorded in the second area to acquire second comparison information representing a signal quality, and determines that the signal quality of the information recorded in the medium is deteriorated, in a case where the second comparison information represents a signal quality higher than that represented by the first comparison information.

Information recording and reproducing device and method for determining deterioration of information recorded in a recording medium

There are provided an optical head and an optical information device capable of downsizing the optical head, and capable of improving the qualities of a focus error signal, a tracking error signal, and a reproduction signal. A light detector () includes a light-receiving unit () for receiving a reflected light beam from an optical disc, and a package () for covering the light-receiving unit (). The package () has a plurality of light guides () formed on a light-receiving surface on the light beam incident side of the light-receiving unit (), and for guiding a reflected light beam to the light-receiving unit (), and a light shield () for shielding a region except for a plurality of the light guides () from light.

Optical head and optical information device

An information recording medium according to the present invention includes at least three information recording layers. If the readout power of a laser beam in reading information from an information recording layer L(n) is identified by Pw(n), and if the readout power of the laser beam in reading information from an information recording layer L(n+a) is identified by Pw(n+a), then a base thickness between the information recording layers is determined so that the intensity of the light when the information recording layer L(n+a) is irradiated with a laser beam having the readout power Pw(n) becomes equal to or lower than that of the light when the information recording layer L(n+a) is irradiated with a laser beam having the readout power Pw(n+a).

Information recording medium, reproducing device and reproducing method

Information recording medium, reproducing apparatus and reproducing method

A method for reading address information from an optical disc with a wobbled track groove includes the steps of: obtaining a sine wave address signal, a first address signal representing a first groove region with sine wave wobbled portions and an inverted phase portion, and a second address signal representing a second groove region with steep inward or outward displacements; multiplying a first reference signal, being phase-locked to, and having the same frequency as, the sine wave address signal, and the first address signal together to obtain a first multiplied signal; multiplying a second reference signal, being phase-locked to, and having a frequency twice as high as, the sine wave address signal, and the second address signal together to obtain a second multiplied signal; integrating the first, multiplied signal and the second multiplied signal separately to obtain a first integral and a second integral, respectively; and adding the first and second integrals together.

Method and apparatus for reading address information from an optical disc medium

At the time of heterodyne detection, information is reproduced constantly in the optimum condition. A method reproduces information recording medium including a reference wobble block which has a first wobble pattern representing a first information content; and an information wobble block which follows the reference wobble block and which has at least one of the first wobble pattern and a second wobble pattern representing a second information and different from the first wobble pattern. The method includes reading the reference wobble block and the information wobble block; comparing a wobble pattern read from the information wobble block with the first wobble pattern of the reference wobble block; judging that information recorded in the information wobble block is the first information or the second information according to the wobble pattern read from the information wobble block; and outputting one of the first and the second information based on the judging result.

Method and an apparatus for reproducing information based on reference wobble block and an information wobble block on an information recording medium

An apparatus for reproducing information that has been digitally recorded on a storage medium includes first and second waveform equalizers. The first waveform equalizer equalizes a read signal, corresponding to the information read out from the storage medium, thereby outputting a first equalized signal. The second waveform equalizer has an equalization characteristic different from that of the first waveform equalizer, outputs a second equalized signal and is selectively used to extract a read clock signal.

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Osaka, Japan

Masahito Nakao