Abstract: An optical disc medium 10 having a wobbled track groove 12 includes three wobble patterns including a flat wobble pattern, a positive pulse wobble pattern, and a negative pulse wobble pattern. In the flat wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is zero such that the track groove is flat. In the positive pulse wobble pattern, the amplitude of the wobble from the length-wise direction of the track groove is positive such that the track groove is wobbled in a first direction perpendicular to the length-wise direction. Further, in the negative pulse wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is negative such that the track groove is wobbled in a second direction opposite to the first direction. Then, three data values can be recorded using three distinctive wobble patterns.

Abstract: A recording medium comprising a recording area, the recording area includes a first area and a second area, the first area includes a frame area, the frame area includes an area in which a second synchronization code sequence and at least a portion of data are to be recorded, and the second area includes an area in which a third synchronization code sequence and a fourth synchronization code sequence are to be recorded.

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: 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.

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 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: An optical disc medium 10 having a wobbled track groove 12 includes three wobble patterns including a flat wobble pattern, a positive pulse wobble pattern, and a negative pulse wobble pattern. In the flat wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is zero such that the track groove is flat. In the positive pulse wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is positive such that the track groove is wobbled in a first direction perpendicular to the lengthwise direction. Further, in the negative pulse wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is negative such that the track groove is wobbled in a second direction opposite to the first direction. Then, three data values can be recorded using three distinctive wobble patterns.

Abstract: An optical disc medium comprises 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 disk includes a groove and a land. Data is recorded on either the land or the groove. A pitch of the groove and a pitch of the land are 0.32 ?m or more. The optical disk has a data efficiency of 80% or more by adopting a format in which other types of user data are added to every plural user data sets. The data efficiency is defined by a ratio of a user data capacity that can be used by a user to a total data capacity of the optical disk.

Abstract: An optical disk device comprising a first light source of a first wavelength, a second light source of a second wavelength, first and second objective lenses for focusing light beams of the first and second wavelengths at a predetermined position, an actuator supporting the first and second objective lenses and movable between first and second positions, focus detecting means, focus computing means for outputting a focus error signal and controlling means for, on receiving the focus error signal, controlling the on/off of the first and second light sources and the position of the actuator in a first direction generally perpendicular to a major surface of the loaded optical disk. While the actuator is moving from the first position to the second position or from the second one to the first one, a semi-focused state is detected from the focus error signal outputted from the focus computing means.

Abstract: 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.

Abstract: An optical disc medium comprises 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 medium comprises 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 medium comprises 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: Method for controlling a laser power used in recording on an optical disk includes: causing the laser to emit a test light emission pattern including a multipulse light emission interval and an at-bottom value continuous light emission interval; receiving the test light emission pattern of the laser to convert the pattern to an electric signal and to thereby obtain a light detection signal; calculating a detection value of a multipulse average value from the average value of the light detection signal, and calculating a bottom detection value from the light detection signal to obtain a light emission power characteristic of the laser on a supplied current based on the detection value of the multipulse average value and the bottom detection value; and controlling the current supplied to the laser based on the light emission power characteristic on the current supplied to the laser.

Abstract: A recording medium comprising a recording area, the recording area includes a first area and a second area, the first area includes a frame area, the frame area includes an area in which a second synchronization code sequence and at least a portion of data are to be recorded, and the second area includes an area in which a third synchronization code sequence and a fourth synchronization code sequence are to be recorded.

Abstract: An information storage medium 100 according to the present invention includes a track 10 that wobbles in a predetermined period and a plurality of pre-pits 21 and 22, which are arranged adjacent to the track. The track has a plurality of frame units 11 and 12. At least one of the pre-pits 21 and 22 is allocated to each of the frame units 11 and 12. Each of the frame units 11 and 12 has a first wobble shape 111, of which the falling portion is sloped more steeply than its rising portion, and/or a second wobble shape 112, of which the rising portion is sloped more steeply than its falling portion. The first wobble shape 111 represents a first type of information and the second wobble shape 112 represents a second type of information. The first and second types of information are different from each other.

Abstract: An optical disc medium comprises 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 medium comprises 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 medium comprises 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.