Thermo-optic information writing process and information support for implementing this process

Claim 2

In a thermo-optic information writing process consisting in heating superficially in a first writing phase by means of a focused radiation beam modulated in intensity a thermosensitive information support comprising a metal layer which covers an organic layer deposited on a substrate, the heat energy released in the metal layer by impact of the beam causes local expansion without change of state of the organic layer; this expansion creating a first relief in the metal layer by stretching situated beyond the elastic limit and short of the rupture elongation of the ductile material forming said metal layer and heating superficially in a second writing phase to modify said first relief locally by a second relief more accentuated than said first relief.

Claim 3

The process as claimed in claim 1, wherein said organic layer is made from at least one basic polymer material in which there has been incorporated at least one plasticizing substance for increasing the thermal expansion coefficient.

Claim 4

The process as claimed in claim 1, wherein said organic layer is deposited from a solution prepared by means of a solvent; the solvent being completely evaporated before depositing said metal layer.

Claim 5

The process as claimed in claim 1, wherein said organic and metal layers are protected by a cover fixed to the information support.

Claim 6

An information support for recording information comprising: a substrate of organic material thermally expanded at a plurality of discrete locations on the surface thereof without change of state and in response to localized heating produced by a focused radiation beam, said localized heating producing deformation and a ductile metal layer deposited on said surface of said substrate and permanently deformed at said locations in response to the thermal expansion of said thermally expanded organic material to form a permanent relief, recording said information, said organic material remaining solid when thermally expanded to totally fill said deformations, the localized heating of said organic substrate in the impact zone of said beam generating expansion without change of state for causing plastic stretching of said metal layer, said plastic stretching being situated beyond the elastic limit but short of the rupture elongation of said ductile metal layer.

Claim 7

An information support for recording information comprising: a substrate of organic material thermally expanded at a plurality of discrete locations on the surface thereof without change of state and in response to localized heating produced by a focused radiation beam, said localized heating producing deformation and a ductile metal layer deposited on said surface of said substrate and permanently deformed at said locations in response to the thermal expansion of said thermally expanded organic material to form a permanent relief, recording said information, said organic material remaining solid when thermally expanded to totally fill said deformations, the localized heating of said organic substrate in the impact zone of said beam generating expansion without change of state for causing plastic stretching of said metal layer, said plastic stretching being situated beyond the elastic limit but short of the rupture elongation of said ductile metal layer.

Claim 8

The information support as claimed in claim 5, wherein said organic layer is formed by at least one basic polymer in which is incorporated an additive having plasticizing properties.

Claim 9

The information support as claimed in claim 6, wherein said basic polymer is a cellulose derivative.

Claim 10

The information support as claimed in claim 6, wherein said basic polymer belongs to the group comprising the polymethacrylates, the polycarbonates, polystyrene and the polyurethanes.

Claim 11

The information support as claimed in claim 6, wherein said additive is a diester of phthalate, adipate, azelate or sebacate type.

Claim 12

The information support as claimed in claim 5, wherein said metal layer is made from a precious metal gold, silver or platinum, from an alloy of these precious metals or from an alloy of these precious metals containing at least one of the metals: nickel, zinc, bismuth, copper, germanium.

Claim 13

The information support as claimed in claim 5, wherein said metal layer is provided with a prerecorded track.

Claim 14

The information support as claimed in claim 5, wherein said metal layer is protected by a cover projecting over the information support.

Claim 15

The information support as claimed in claim 10, wherein said metal layer is a Cu 20 Au 80 alloy.