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AssigneeSharp Kabushiki Kaisha
InventorsChiaki Kiyooka, Nobuo Ogata
Estimating the term…
In an optical recording medium, a groove G and/or a land L composing a recording track includes an interrupted portion of a predetermined length in a direction of the recording track, and the interrupted portion is a clock mark to obtain a clock signal. When (clock mark length C1)/(beam spot size D1)=CM, CM≦1.0. This reduces a region to record the control signal, thereby enabling high-density recording and reproduction, reproducing a control signal having a waveform free from distortion, and generating a clock signal in a state of little jitter.
An optical recording medium in which a groove and/or a land composing a recording track includes an interrupted portion of a predetermined length in a direction of the recording track, and the interrupted portion is a control signal mark to obtain a control signal, wherein:
An optical recording medium in which a groove and/or a land composing a recording track includes an interrupted portion of a predetermined length in a direction of the recording track, and the interrupted portion is a control signal mark to obtain a control signal, wherein:
An optical recording medium in which a groove and/or a land composing a recording track includes an interrupted portion of a predetermined length in a direction of the recording track, and the interrupted portion is a control signal mark to obtain a control signal, and which is capable of recording and/or reproduction by laser light having wavelengths λ1 and λ2 (λ1>λ2), wherein:
An optical recording medium in which a groove and/or a land composing a recording track includes an interrupted portion of a predetermined length in a direction of the recording track, the interrupted portion is a control signal mark to obtain a first control signal and a second control signal is recorded by giving a wobble to at least one of side walls of the groove, wherein:
An optical recording medium in which a groove and/or a land composing a recording track includes an interrupted portion of a predetermined length in a direction of the recording track, the interrupted portion is a control signal mark to obtain a first control signal and a second control signal is recorded by giving a wobble to at least one of side walls of the groove, wherein:
An optical recording medium in which a groove and/or a land composing a recording track includes an interrupted portion of a predetermined length in a direction of the recording track, and the interrupted portion is a control signal mark to obtain a first control signal, and a second control signal is recorded by giving a wobble to at least one of side walls of the groove, and which is capable of recording and/or reproduction by laser light having wavelengths λ1 and λ2 (λ1>λ2), wherein:
A recording and reproducing method for an optical recording medium, capable of performing recording and/or reproduction of information with respect to an optical recording medium in which a groove and/or a land composing a recording track includes an interrupted portion of a predetermined length in a direction of the recording track, and the interrupted portion is a control signal mark to obtain a control signal, wherein:
A recording and reproducing method for an optical recording medium, capable of performing recording and/or reproduction of information with respect to the optical recording medium in which a groove and/or a land composing a recording track includes an interrupted portion of a predetermined length in a direction of the recording track, and the interrupted portion is a control signal mark to obtain a first control signal, and a second control signal is recorded by giving a wobble to at least one of side walls of the groove, wherein:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Tracks: width or depth
Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the…:…
Arrangement of the information on the record carrier, e.g. form of tracks , actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped;…:…
Arrangement of the information on the record carrier, e.g. form of tracks , actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped;…:…
Term ended 1 Aug 2022 (estimated)
The present invention relates to an optical recording medium including recording tracks for recording a signal, which are made up of at least either one of grooves and lands, and an optical recording and reproducing device using this optical recording medium as well as a recording and reproducing method for the optical recording medium.
In recent years, for rewritable high-density optical recording media, and in particular magneto-optical recording media, there has been propose d and widely adopted such a format as to realize a large storage capacity ranging between 5 GB and 7 GB on one side of a disk having a diameter of 12 cm which is a common size of a CD. In that case, the thickness of a disk plate is reduced to 0.6 mm so as to allow an optical pickup to have a numerical aperture NA=0.6. Moreover, a single plate structure is adopted to attain magnetic field modulation, where a recording/reproducing laser wavelength λ=630 nm to 650 nm, a track pitch−0.6 μm, and recording line density=0.20 μm/bit.
As a recording format to realize the above large-capacity recording is adopted a land/groove recording system which is capable of recording and reproducing a signal in both lands and grooves, and is effective in attaining high density.
Additional objects, features, and strengths of the present invention will be made clear by the description below. Further, the advantages of the present invention will be evident from the following explanation in reference to the drawings.
FIG. 1 is an explanatory view showing a main part of an optical recording medium according to one embodiment of the present invention, and in particular a state of formation of a land and grooves.
FIG. 2(a) is a waveform diagram showing a TPP signal which is detected by a 2-division photodetector when a laser spot scans a groove G shown in FIG. 1.
The following will explain embodiments of the present invention with reference to FIGS. 1 through 21. Note that, a laser beam spot size used in the present explanation is set to have an intensity which is 1/e2 with respect to the center intensity of a laser emission beam.
As shown in FIG. 1, an optical recording medium 1 according to the present invention is made up of, for example, a magneto-optical recording medium. The optical recording medium 1 adopts a land/groove recording system and has grooves G and lands L making up a recording track. The grooves G and the lands L are alternately provided in a direction of a diameter (“diameter direction”, hereinafter) of the disk-shaped optical recording medium 1. The groove G and the land L have widths GW and LW, respectively, which are set to be substantially the same.
The groove G and the land L are either concentrically or spirally formed, thereby having either a spiral structure or a concentric circular structure.