Bourns Incorporated

Wayne P Bosze

Ronald E Thomas, Jr

Ronald L Froebe

Philip F Weingartner

Gordon McClure

An electrically conductive polymer film composition includes a polymeric resin, an electrically conductive substance intimately mixed in sufficient quantity with the polymeric resin to render the polymeric resin electrically conductive, and particles, such as fibers or spheres of appropriate size, admixed with the polymer composition in sufficient quantity so that in the cured polymer film the particles protrude from the surface of the film and render the surface uneven on a micro scale. The cured polymer film composition of the invention is incorporated in potentiometers and similar electric and electronic devices as a thick film where a contact wiper rides substantially continuously in contact with the protruding fibers.

Electrically conductive polymer thick film of improved wear

An improved resistive element comprises a film-type resistive layer applied to an insulative substrate and then fired. An array of discrete, spaced apart islands of predominantly conductive material is then applied to the resistive layer in a repetitive pattern having predetermined inter-island spacing. The islands have a conductivity that is substantially greater than the conductivity of the resistive layer. Preferably, the islands are of substantially uniform shape and size. In one preferred embodiment, the islands are formed of a conductive thick film ink that is screen-printed onto a cermet resistive layer through an appropriate mask, and then fired. In another preferred embodiment, the islands are formed of a conductive metal that is applied to the resistive layer by vapor deposition, sputtering, or ion implantation through a suitable mask. Either embodiment of the invention provides a resistive element with lower contact resistance and improved contact resistance stability than prior art film-type resistive elements, while maintaining good linearity, setability, and resolution.

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Riverside, CA, United States of America

Wayne P Bosze