Thin film phosphor screens on fiber optic faceplates

Abstract

Cathodoluminescent phosphor screens are commonly used in display devices such as CRT's and image intensifiers. Conventional methods of fabricating such screens involve the physical deposition of phosphor powder on an appropriate substrate, such as clear glass. In addition, high resolution display devices are now utilizing thin powder layers on fiber optic faceplates, greatly enhancing their resolution capabilities. At present, a typical resolution achievable with powder screens on fiber optic faceplates is approximately 50 lp/mm, or about 10 X 10 micron pixel size, and is primarily limited by the faceplate resolution. However, as the ultimate resolution of fiber optic faceplates is improved (i.e., as the fiber diameters are reduced), phosphor powder particle size and thickness will also have to be reduced to maintain high overall screen resolution. For example, in order to achieve a 1 micron resolution, a phosphor screen 1 micron thick would be required with 1 micron diameter or less particle size. However, it is not likely that current screen manufacturing technologies can readily achieve the desired particle size, thickness, and uniformity requirements to further improve resolution.