Abstract: An optical disc medium compares a track groove, along which main information is recorded. The track groove is divided into a plurality of blocks. The plurality of blocks each include a plurality of frames. The plurality of frames each include one shape of wobbles indicating sub information, among a plurality of prescribed shapes of wobbles. The plurality of blocks each have address information. The address information is represented by a string of at least one piece of sub information represented by the shape of wobbles of at least one of the plurality of frames.

Abstract: An optical disc is provided having marks for dispersed addresses that can be easily detected with high precision. A dispersed address includes synchronization marks, positive marks, and negative marks. The synchronization marks, positive marks, and negative marks are formed along a groove as partial discontinuities or partial modifications in the wobbled groove.

Abstract: When information is reproduced in an optical disk of high recording density or of low recording density, a main beam and sub-beams are emitted onto adjacent tracks. The main beam has a shape longer in a direction perpendicular to the tracks. When the optical disk of high recording density is reproduced, cross talk components from adjacent tracks included in signals reproduced from reflection light of the main beam are canceled by using signals reproduced from reflection lights of the sub-beams. When the optical disk of low recording density is reproduced, information is reproduced with a beam. Thus, two types of optical disks can be reproduced with a simple structure in a compatible way. In the cross talk canceling, discrimination marks formed along the tracks at constant distances are reproduced, and a time difference between the main beam and the sub-beams is corrected precisely by using track jump and detection of discrimination marks.

Abstract: An optical disc medium, including a plurality of sector groups each being made up of multiple contiguous sectors on a track, is provided. In this optical disc medium, the location information of each of those sector groups is divided into a predetermined number of information pieces and distributed to associated sectors on the same track.

Abstract: An optical disc having marks for dispersed addresses that can be easily detected with high precision. A dispersed address comprises synchronization marks, positive marks, and negative marks. Synchronization marks, positive marks, and negative marks are formed along a groove as partial discontinuities or partial modifications in the wobbled groove.

Abstract: On an optical disk medium according to the present invention, address information is recorded along a wobbling track groove 2. The track groove 2 is made up of a plurality of unit sections 22, 23. Each of these unit sections 22, 23 has side faces that are displaced periodically in a disk radial direction. This displacement oscillates at a single period in a tracking direction. However, the displacement pattern differs depending on “each bit of address information (subdivided information)” allocated to each of the unit sections 22, 23.

Abstract: An optical disk medium includes a track groove thereon. On the optical disk medium, information is recorded along the track groove on a block unit basis. The block unit has a predetermined length. The block unit having the predetermined length includes a number of sub-blocks that are arranged along the groove. A sub-block mark is provided within each of the sub-blocks and used to identify the sub-block.

Abstract: In areas on an optical disk wherein defects are detected frequently, recording is carried out while the recording density of information blocks is lowered and the amount of picture information is reduced at the same time so that digital video signals can be recorded even when defects owing to dust and flaws are present on the optical disk and so that picture losses can be prevented from occurring during reproduction.

Abstract: A light source device can attain a stable output of a harmonic even when there occurs a change in the ambient temperature or fluctuation in the output power. The light source device is provided with a semiconductor laser source (4), an optical waveguide-type QPM-SHG device (5) for generating a second harmonic from light emitted from the semiconductor laser source (4), a wavelength control means (7) for controlling a wavelength of light emitted from the semiconductor laser source (4), a means for slightly fluctuating wavelength (8) for changing a wavelength of light emitted from the semiconductor laser source (4) and a means for detecting a change in output light power of the optical waveguide-type QPM-SHG device (5) that occurs when a wavelength of light emitted from the semiconductor laser source (4) is changed.

Abstract: An optical disc having marks for dispersed addresses that can be easily detected with high precision. A dispersed address comprises synchronization marks, positive marks, and negative marks. Synchronization marks, positive marks, and negative marks are formed along a groove as partial discontinuities or partial modifications in the wobbled groove.

Abstract: An optical recording medium comprises a plurality of identifiers in association with address information, wherein: each identifier is provided on the optical recording medium; and each identifier comprises at least one of: a first pattern provided on the optical recording medium and representing a first code expressed by one bit; a second pattern provided on the optical recording medium and representing a second code expressed by one bit; and a third pattern provided on the optical recording medium and representing a third code expressed by one bit.

Abstract: A multivalued information recording method in which energy applied to information units on a recording medium is varied to record multivalued information. In accordance with a relationship between the multivalued information in a predetermined information unit and the multivalued information in information units adjacent to the predetermined information unit, the energy applied to the predetermined information unit is decided.

Abstract: In an optical disc drive, a laser light source emits a laser beam having an intensity changeable with the amount of drive current supplied. A first photodetector receives the laser beam reflected from an optical disc, thereby generating a readout signal. A second photodetector receives the laser beam, generates an electric signal representing the power of the laser beam received, and outputs the electric signal as a light quantity detection signal. A feedback control loop compares the level of the light quantity detection signal with a predetermined target value and regulates the drive current such that the level of the light quantity detection signal approaches the target value. In reading data from the optical disc, the target value is changed so as to compensate for a variation of the sensitivity of the second photodetector, thereby controlling the power of the laser beam emitted from the laser light source.

Abstract: An IC tag unit has an IC unit for storing unique identification information, a first coil operable to produce a first induction current by electromagnetic induction resulting from movement relative to a magnetic field in which north and south poles are separated by a specific distance, a first rectifier operable to produce a first rectified current by rectifying the first induction current, and a regulator operable to generate a specific voltage from the first rectified current and supplying the voltage to the IC unit.

Abstract: 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.

Abstract: An information reproduction apparatus of the present invention comprises a rotating section 2 for rotating an information carrier 1 on which a unit of continuous information capable of being continuously read out is recorded, a CLV control section 9 for controlling the rotating section in such a manner that the information carrier is rotated at a constant linear velocity, a CAV control section 9 for controlling the rotating section in such a manner that the information carrier is rotated at a constant angular velocity, a rotation control selection 14 for selectively operating the CLV or CAV control section, and an information determination section 14 for detecting an information length of the continuous information. The rotation control selection section is constructed in such a manner as to selectively operate the CLV or CAV control section based on a result of the detection of the information length of the continuous information.

Abstract: An optical disc is provided having marks for dispersed addresses that can be easily detected with high precision. A dispersed address includes synchronization marks, positive marks, and negative marks. The synchronization marks, positive marks, and negative marks are formed along a groove as partial discontinuities or partial modifications in the wobbled groove.

Abstract: A laser control unit, a laser control circuit and a laser-power adjustment method are provided which are capable of controlling laser power precisely, even if an error is produced in the duty of an optical pulse.

Abstract: An optical disk information recording and reproducing device (100), which is used for recording and reproducing information on an optical disk (10), includes a system controller (19), a tracking control portion (15), a focus control portion (16) and an aberration correction portion (17). The system controller (19) adjusts a control parameter for recording and reproducing control of the optical disk (10) by using a tracking error signal TE that is detected from an region (30) having a wide track pitch on the optical disk (10). The tracking control portion (15), the focus control portion (16) and the aberration correction portion (17) record and reproduce information on the optical disk (10) by using the adjusted control parameter.

Abstract: An apparatus of the present invention is an optical disk apparatus for irradiating with a laser beam an optical disk on which address marks are recorded at intervals based on a pulse width modulation method and for reproducing data from a reproduced signal based on reflected light. The apparatus includes: a pulse signal reproduction section for producing a reproduced pulse signal from the reproduced signal based on a threshold value; a threshold value production section for producing the threshold value based on the reproduced pulse signal; and a gate signal production section for producing an address gate signal at a timing when the address mark is reproduced.