A 6 × 6-in 20-lpi electroluminescent display panel

Over the last two years, we have been working on a solution of the solid-state display addressing problem which consists of building the addressing circuits (and eventually, also scanning or decoding circuits) directly on the panel, and fully integrated with the particular display medium. The technique utilized for this approach is that of a vacuum-deposited thin-film transistor matrix. In this paper, we report on the design, construction, and performance of a 12 000 element EL panel, suitable for alphanumeric, vectorgraphic, and monochrome TV image presentation. The basic circuit, repeated at every picture element, consists of an X-Y-addressed logic transistor, a power transistor, and a storage capacitor. The entire circuit was fabricated through multiple evaporations in a multisource system using one pumpdown cycle. The finished thin-film circuit is covered with a sprayed EL-phosphor. An evaporated Au/PbO layer forms the continuous top electrode. The entire display panel is finally sealed with a glass cover plate. Reproducible fabrication of good-quality displays was achieved, with >99 percent of the elements operational. Excellent alphanumeric displays with very few defects were demonstrated. Contrast ratios >50:1 (ON:OFF under dark ambient) were obtained. Power consumption under typical alphanumeric display conditions was below 1 W, with a peak brightness of 40 fL.