Embossed holograms formed on hard metal surfaces
AssigneeAmerican Bank Note Holographics, Inc.
InventorsSalvatore F. D'Amato, Edward H. Weitzen
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Abstract
Embossed holograms or diffraction patterns are formed on hard, unembossible metal substrates such as steel sheet metal. The hard metal substrate has a soft embossible metal layer such as tin formed on it, and holograms are embossed thereon by means of a surface relief, metal master. The soft metal layer must be sufficiently thick to accommodate the deepest surface relief pattern. For tinplate, the embossing can be preformed at room temperature. Among other things, the process produces tinplates and tin cans with embossed holograms.
Claims14
A method of forming an embossed hologram on a first metal surface having a first hardness from a metal master surface relief pattern having a second hardness comparable or significantly less than said first hardness comprising the steps of:
- forming a layer of a second metal on said first metal surface, said second metal having a thickness in excess of a maximum depth of said master surface relief pattern, and having hardness much less than that of metal master, and
- compressing said second metal layer with said first metal layer and said metal master sufficient to cause second layer outside surface to substantially conform to surface relief pattern.
A method of forming an embossed diffraction pattern on a tin-plating portion of a metal comprising the steps of:
- forming a metal master surface relief pattern of the diffraction pattern;
- tin-plating at least one portion of the metal to a thickness sufficient to accommodate a maximum relief depth of said metal master;
- maintaining said tin-plating within a temperature range where said tin-plating has a yield strength substantially less than that of said metal master;
- and
- impressing said metal master surface relief pattern against said tin-plating portion to cause surface thereon to conform substantially to surface relief pattern.
A method of forming an embossed diffraction pattern on a tin can comprising the steps of:
- forming a metal master surface relief pattern of the diffraction pattern;
- selecting a tin can having a tin coating of thickness sufficient to accommodate a maximum relief depth of said metal master;
- maintaining said tin coating within a temperature range where said tin coating has a yield strength substantially less than that of said metal master;
- and
- impressing said metal master surface relief pattern against said tin coating to cause surface thereon to conform substantially to surface relief pattern.
Dependencies are inferred from the claim text.