Method of producing an exact edge on an etched article

Abstract

Abstract AN EDGE MORE EXACTLY CONFORMING TO THE OUTLINES OF AN ETCHING MASK IS PRODUCED BY A METHOD WHICH INCLUDES PROVIDING A METALLIC FOIL WHOSE RESISTANCE TO ETCHING DECREASES ALONG THE DEPTH OF ITS THICKNESS FROM AT LEAST A FIRST SURFACE, APPLYING AN ETHCING MASK TO AT LEAST SAID FIRST SURFACE OF THE FOIL, AND SUBJECTING THE MASKED SURFACE TO AN ETCHING AGENT. THE DIFFERENTIAL RESISTANCE TO ETCHING AVOIDS OR MINIMIZES UNDERCUTTING OF THE EDGES OF THE THICK FOIL. THE FOIL MAY BE ACTED ON BY THE ETCHING AGENT FROM ONE OR MORE SURFACES AND IN EACH CASE SHOULD DECREASE IN RESISTANCE FROM THE SURFACE BEING ACTED ON. THE FOIL MAY COMPRISE A SERIES OF DISCRETE LAYERS HAVING PREDETERMINED THICKNESS RELATIONSHIPS WITH EACH OTHER. TO PROVIDE A CONTINUOUS CHANGE OF RESISTANCE TO THE ETCHING AGENT WHICH IS INVERSELY PROPORTIONAL TO THE DISTANCE FROM THE UNMASKED SURFACE, THE DISCRETE LAYERS OF MATERIAL HAVING DIFFERENT RESISTANCE VALUES MAY BE SUBJECTED TO A HIGH TEMPERATURE DIFFUSION TREATMENT WHEREBY THEIR CHANGE IN RESISTANCE FOLLOWS A SMOOTH CURVE.

Inventors

• 👤 Siemens R Von

Bibliographic Details