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US 2004/0174797 A1Published application
Method for recording and reproducing holographic data and holographic recording medium
AssigneeTDK Corporation
InventorTakuya Tsukagoshi
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AssigneeTDK Corporation
InventorTakuya Tsukagoshi
Estimating the term…
A holographic recording medium includes a recording layer in which data are to be recorded as phase information of light by projecting a signal beam and a reference beam thereonto, a reflective surface disposed on the opposite side of the recording layer as viewed in the direction of signal beam and reference beam incidence on the holographic recording medium and formed with a convex pattern or a concave pattern having a trapezoidal cross-section, a minimum width of a convex surface of the convex pattern or a concave surface of the concave pattern being set equal to or larger than a beam spot diameter of the signal beam or the reference beam at a diffraction limit thereof. According to the thus constituted holographic recording medium, it is possible to easily remove noise light contained in a signal beam and a reference beam.
A holographic recording and reproducing method for recording holographic data in and reproducing holographic data from a holographic recording medium comprising at least a recording layer in which data are to be recorded as phase information of light by projecting a signal beam and a reference beam thereonto, a beam spot incidence region for the signal beam and the reference beam disposed on the opposite side of the recording layer as viewed in the direction of signal beam and reference beam incidence on the holographic recording medium and a filter region formed in at least a part of a periphery of the beam spot incidence region, the holographic recording and reproducing method comprising steps of setting a beam spot diameter of the signal beam or the reference beam at a diffraction limit thereof equal to or smaller than a minimum width of the beam spot incidence region and projecting the signal beam or the reference beam onto the holographic recording medium.
A holographic recording medium comprising at least a recording layer in which data are to be recorded as phase information of light by projecting a signal beam and a reference beam thereonto, a beam spot incidence region of the signal beam and the reference beam disposed on the opposite side of the recording layer as viewed in the direction of signal beam and reference beam incidence on the holographic recording medium and a filter region formed in at least a part of a periphery of the beam spot incidence region, a minimum width of the beam spot incidence region being set equal to or larger than a beam spot diameter of the signal beam or the reference beam at a diffraction limit thereof.
A holographic recording medium comprising at least a recording layer in which data are to be recorded as phase information of light by projecting a signal beam and a reference beam thereonto, a reflective surface disposed on the opposite side of the recording layer as viewed in the direction of signal beam and reference beam incidence on the holographic recording medium and formed with a convex pattern or a concave pattern having a trapezoidal cross-section, a minimum width of a convex surface of the convex pattern or a concave surface of the concave pattern being set equal to or larger than a beam spot diameter of the signal beam or the reference beam at a diffraction limit thereof.
Dependencies are inferred from the claim text.