Abstract: Disclosed herein are a disc recording medium, a recording apparatus and a playback apparatus, more concretely, the present invention provides a disc recording medium wherein a circular track is created in advance to be used for recording data as a groove or a land, said track is wobbled to contain approximately fixed number of wobbling periods as counted in a longitudinal direction of said track, and said track includes rotational-angle marks each showing a predetermined rotational angular position on said disc recording medium. As a result, the precision and the reliability of recording can be attained.

Abstract: A disc tray for holding a disc on which an information signal is recorded and which can be loaded into a disc drive apparatus in a state where the disc tray holds the disc, the disc tray having an overall body formed into a thin plate-like shape and including a disc-receiving recess having an inner diameter larger than the diameter of a recording and/or reproducing disc and a depth larger than the thickness of the disc and arranged to removably hold the disc while having gaps in a direction in parallel with the surfaces of the disc and in a direction of the thickness of the disc, a bottom opening formed along the widthwise directional center of the disc tray in a range from substantially the central portion of the bottom portion of the disc-receiving recess to an end of the bottom portion and having a shape that the end of the bottom is opened, and a plurality of disc-separation-preventive portions formed to project into the disc-receiving recess from outside of the disc-receiving recess in such a manner that

Abstract: A disc tray for holding a disc on which an information signal is recorded and which can be loaded into a disc drive apparatus in a state where the disc tray holds the disc, the disc tray having an overall body formed into a thin plate-like shape and including a disc-receiving recess having an inner diameter larger than the diameter of a recording and/or reproducing disc and a depth larger than the thickness of the disc and arranged to removably hold the disc while having gaps in a direction in parallel with the surfaces of the disc and in a direction of the thickness of the disc, a bottom opening formed along the widthwise directional center of the disc tray in a range from substantially the central portion of the bottom portion of the disc-receiving recess to an end of the bottom portion and having a shape that the end of the bottom is opened, and a plurality of disc-separation-preventive portions formed to project into the disc-receiving recess from outside of the disc-receiving recess in such a manner that

Abstract: A disc tray for holding a disc on which an information signal is recorded and which can be loaded into a disc drive apparatus in a state where the disc tray holds the disc, the disc tray having an overall body formed into a thin plate-like shape and including a disc-receiving recess having an inner diameter larger than the diameter of a recording and/or reproducing disc and a depth larger than the thickness of the disc and arranged to removably hold the disc while having gaps in a direction in parallel with the surfaces of the disc and in a direction of the thickness of the disc, a bottom opening formed along the widthwise directional center of the disc tray in a range from substantially the central portion of the bottom portion of the disc-receiving recess to an end of the bottom portion and having a shape that the end of the bottom is opened, and a plurality of disc-separation-preventive portions formed to project into the disc-receiving recess from outside of the disc-receiving recess in such a manner that

Abstract: For recording data into a disc-like recording medium without any lower linear density in data tracks in the lead out zone even in the CAV mode, a radial position on the recording medium of an n-th one of the sectors is calculated to generate a position information; a write frequency is determined based of the position information; a number of bits which are to be recorded into the n-th one of the sectors is calculated based on a following expression (1): F 2 ⁢ π · N · 2 ⁢ π P ⁢ ( R 0 2

Abstract: An optical disc and a disc cartridge for accommodating the optical disc, wherein the disc cartridge accommodates a disc non-symmetrical in cross-section relative to the center of thickness of the disc. The disc cartridge includes a main cartridge body portion and an opening/closure mechanism, in which the main cartridge body portion has an aperture via which to insert or take out the disc. The main cartridge body portion is configured for accommodating the disc only in the regular state of the disc which permits recording and/or reproduction of the disc. The opening/closure mechanism opens or closes the aperture.

Abstract: An optical disc and a disc cartridge for accommodating the optical disc, wherein the disc cartridge accommodates a disc non-symmetrical in cross-section relative to the center of thickness of the disc, in which disc cartridge includes a main cartridge body portion and an opening/closure mechanism. The main cartridge body portion has an aperture via which to insert or take out the disc. The main cartridge body portion is configured for accommodating the disc only in the regular state of the disc which permits recording and/or reproduction of the disc. The opening/closure mechanism opens or closes the aperture.