Holographic optical data storage medium
First Claim
1. An optical data storage medium comprising a substrate which has formed therein at least one terraced depression whose terraces are located depthwise in said substrate at interference planes corresponding to a volume phase reflection hologram so that said terraced depression operates as a volume phase reflection hologram which, when illuminated, provides predetermined optical effects, said substrate being responsive to predetermined external stimuli to produce detectable changes in said predetermined optical effects such that said changes operate as a means for encoding information in said substrate.
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Accused Products
Abstract
A hologram is fabricated by opening a volume phase reflection hologram formed in a recording medium such as a positive photoresist. The opening occurs by forming a second hologram, such as an off-axis hologram, in the same recording medium. The opened hologram can be replicated in metal and the metal can be used to emboss the fringe pattern of the opened hologram into plastic. A full range of colors in the visible spectrum may be obtained by metallizing the embossed plastic structure and then by overcoating it with appropriate clear dielectric layers.
150 Citations
7 Claims
- 1. An optical data storage medium comprising a substrate which has formed therein at least one terraced depression whose terraces are located depthwise in said substrate at interference planes corresponding to a volume phase reflection hologram so that said terraced depression operates as a volume phase reflection hologram which, when illuminated, provides predetermined optical effects, said substrate being responsive to predetermined external stimuli to produce detectable changes in said predetermined optical effects such that said changes operate as a means for encoding information in said substrate.
Specification