Thin film thermal print head

Abstract

A dielectric substrate for a thin film dot matrix thermal print head has its working surface etched or otherwise treated for selective removal of the dielectric material in all areas that are to constitute electrical connectors for the resistance heater print elements, to a depth approximately equal to the sum of the thicknesses of all of the conductive films to be applied to the substrate surface in those areas, following which the working surface of the substrate is selectively coated with films of high-resistance electrically conductive material and low-resistance conductive material, with suitable adhesion films as required, to complete the operating elements of the print head. An outer protective wear-resistant film may also be employed on the entire print head surface or on only the electrical connector areas. The print head has its resistance heater print elements and its blank spaces all raised to approximately the same level as the outer surfaces of the electrical connectors affording improved performance and longer operating life; the etching of the substrate is effected by a process that leaves positive transition slopes to assure effective electrical connections to the print elements.

Dependencies are inferred from the claim text.