US 4,788,129 A · High contrast optical memory tape

Abstract

A medium in tape form for laser recorded optical information featuring a gelatin layer having a thin black crust at the top of the layer. The crust is formed by developed black filamentary silver particles within the top 0.5 micron of a gelatin colloid matrix. The remainder of the colloid matrix is substantially clear gelatin and a reflective metallic layer is disposed below the gelatin. The tape may be disposed on reels and may be pre-patterned during formation of the crust with indicia, such as servo track guides or timing marks. User data may be recorded by modification or by displacing the black silver particles in the crust with a laser to expose the reflective underlayer. A laser or other light source is used to read data on the medium with optical contrast between the black surface and the reflective metallic layer underlying the gelatin layer which can be observed in the recorded spots.

Claims10

Dependent claims

Optical memory tape for laser recording optical information comprising,

a self-supporting, flexible web backing,
a vacuum or vapor deposited reflective metallic layer over said web backing,
a planar optical storage layer disposed over the reflective metallic layer, said optical storage layer having a planar crust of filamentary and oblong black silver particles within the top one-half micron of the layer distal to the backing and substantially clear gelatin below the crust.

Dependencies are inferred from the claim text.

High contrast optical memory tape

Life of this patent

High contrast optical memory tape

Life of this patent

Abstract

Claims10