Optical disc structure
AssigneeEastman Kodak Company
InventorDennis G. Howe
Life of this patent
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Abstract
An optical disc of the type having a thermally deformable recording layer overlying a reflectively surfaced support features a crenelated disc support surface having grooves of predetermined depth and interleaved lands arranged in a spiral or concentric pattern. The recording layer's outer surface is nominally planar so that the differences in thickness between "over-land" and "over-groove" portions thereof impart high phase-shift contrast to light of a given read wavelength.
Claims11
In an optical disc of the type having a recording stratum including a thermally deformable recording layer overlying a reflectively surfaced support, the improvement wherein said support surface is crenelated, having a plurality of substantially continuous and uniform-depth grooves and interleaved lands arranged in a spiral or concentric pattern, and said recording stratum has a nominally planar outer surface whereby the thickness of recording stratum portions respectively overlying grooves and lands of said support surface differ in accordance with said groove depth.
In an optical disc of the type having a recording stratum including a thermally deformable recording layer overlying a reflectively surfaced support, the improvement wherein said support surface is crenelated, having a plurality of continuous, uniform-depth grooves defining radially-spaced spiral or concentric track regions and with interleaved land regions of uniform height, and said recording stratum has a nominally planar outer surface whereby the thickness of recording stratum portions respectively overlying the track regions and the land regions are predeterminedly different.
Dependencies are inferred from the claim text.