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US 4,288,528 AGranted
Method of making an embossed pattern on an information bearing substrate
AssigneeThomson-CSF
InventorsJean E. Picquendar, Michel Marchal, Jean C. Dubois, Eugene Duda
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Abstract
An improved process for forming an embossed pattern through the use of a writing concentrated beam opening holes in a film capable of undergoing residue free evaporation. A layer of photoresist is overlayed with the film and upon being exposed and processed the layer supplies the prospective embossed pattern.
Claims10
A process for optically recording video frequency signals as an embossed pattern on the flat surface of a disc forming a substrate comprising:
- (a) coating upon said flat surface a layer of photoresist material having a thickness at least equal to the depth of the resulting embossed pattern, the coated photoresist layer adhering to said flat surface;
- (b) depositing upon said layer a film of residue-free, evaporable material having a thickness sufficient for masking said layer against actinic radiation, said film adhering to said layer of photoresist material;
- (c) irradiating said film in situ along the prospective embossed areas of said pattern with a focussed writing beam from a coherent light source, said irradiation selectively evaporating said film from said area thereby opening holes in said film;
- (d) irradiating said layer of photoresist material in situ through the thus opened holes in said film with actinic radiation;
- (e) selectively dissolving said photoresist layer to remove the irradiated portions of said photoresist material facing said holes.
2 more elements
Dependencies are inferred from the claim text.