Process for making color television screens by electrophoretic deposition

Abstract

This disclosure sets forth a process for electrophoretically depositing patterns of image-related compounds on the inner surface of the faceplate of shadow-mask-type television cathode ray picture tubes. The process comprises the depositing of a pattern of groups of periodically repeating electrically conductive stripes of predetermined graduated length from relatively long to relatively short. Both ends of stripes of similar length, starting with the relatively long stripes, are electrically excited with a charge of a first polarity by means of conductive contact strips during immersion in an electrolytic bath including an image-related compound having particles charged with a potential opposite in polarity to said first polarity for electrophoretic deposition of the particles on the stripes. Both ends of stripes of successively shorter lengths are than serially electrically excited in conjunction with a different bath including a different image-related compound for electrodeposition on the respective stripes. By electrically contacting both ends of the stripes, the effect of a single discontinuity in the electrical conductivity of any of the stripes is nullified, as any stripe having such a discontinuity is electrophoretically coated along its entire length.