Two-color storage tube

A direct-view storage tube has been developed which is capable of displaying stored information in either of two colors or in intermediate hues. The operating principle is based on the fact that flood electrons which pass through the holes in the storage mask when the storage-surface potential is near cutoff fall within small areas on the viewing screen opposite the storage-mask holes; whereas flood electrons which pass through the holes when the potential is near its maximum, i.e., flood-gun-cathode potential, fall on larger overlapping areas on the viewing screen. The viewing screen consists of a pattern of two phosphors: one occupies small areas in register with the storage-mask holes, and the other occupies areas surrounding the first. The tube, which has a 10-inch diameter, can be operated with simple circuitry, essentially the same as that required for conventional half-tone storage tubes. When the performance of this tube is compared with that of conventional half-tone storage tubes, it can be seen that a moderate sacrifice in resolution was made in order to replace the half-tone monochromatic range with a system of two primary colors and intermediate hues. This system permits the color coding of stored information that provides a vivid qualitative or semiquantitative representation of a variable in the display. The design and performance considerations for the tubes are discussed and future investigations for this type of tube are outlined.