A thin-film integrated incandescent display

Incandescent alphanumeric displays using a 16-bar format are obtainable today. They employ 1-ml incandescent tungsten helices strung between support posts. This paper describes a new incandescent display device, fabricated by microelectronic thin-film techniques. Such techniques allow high-resolution dot-matrix displays to be produced with all the cost advantages obtained from the employment of modern LSI thin-film processing. The device uses a ceramic substrate covered with a thick layer of glass. Holes are produced in the laminate and filled with metal to eventually form the element support posts. A thin layer of refractory metal is deposited on the glass. The metal and glass are then etched to produce a field of free-standing microfilaments. The resulting display panel can be driven by simple integrated circuits, and the efficiency of the device, operating at 1200°C, is better than quoted for most light-emitting diodes (LED's).