| 摘要 |
<p>A data card for optical information featuring a gelatin layer (25) having a thin black crust (26) at the top of the layer. The crust is formed by developed black irregular oblong silver particles within the top 0.5 micron of the gelatin colloid matrix. The remainder of the colloid matrix is substantially clear gelatin and a reflective metallic layer is disposed below the gelatin. The strip is laminated into a wallet-size card and may be pre-patterned during formation of the crust with control indicia or pre-recorded data. User data (18, 19) may be recorded by modifying 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 metallic layer underlying the gelatin layer which can be observed in the recorded spots.</p> |
