Characteristics of a Transmission Control Viewing Storage Tube with Halftone Display

A storage tube is described which maintains a bright visual display, using a charge pattern stored on an insulating layer to grid control the transmitted viewing beam. This insulating layer is a part of an image amplifier system, whose operation and characteristics are discussed. The factors affecting background uniformity and viewing duration have been investigated. Methods of extending the viewing duration by electrically compensating for ion landing have been developed. Erasure, which prepares the surface for the writing of new information, may either be over-all erasure of the entire picture, or selective erasure of only that area where new information is to be written. The present tubes will display a halftone picture of good quality for 30 seconds without compensation, and for over 3 minutes with compensation, after writing has stopped. The writing process can be accomplished in 1/30 second for a complete halftone picture. The resolution is over 500 lines on a 4-inch diameter screen, and there are at least 5 distnguishable halftone steps. As a radar indicator, this tube provides a flickerless display of the complete radar picture, which is bright enough for daylight viewing.