Design of a High-Resolution Electrostatic Cathode Ray Tube for the Flying Spot Store

High-resolution cathode ray tubes (CRT's) with electrostatic deflection are normally limited to relatively small deflection angles because of beam-focusing effects introduced by the deflection plates. The deflection distortion causes a loss of resolution at the edges of the screen and severely limits the usable screen diameter of high-resolution tubes. A large-capacity, high-speed, semipermanent memory, 1 " denoted as the flying spot store, has recently been developed for an experimental electronic telephone switching system. 3 One of the critical components of this memory is an electrostatically deflected CRT. The tube is used to provide random access to binary information stored in the form of transparent or opaque dots on photographic plates, as shown in Fig. 1. The electron beam is deflected to the desired address on the screen of the CRT, the luminescent spot is then focused onto an array of n informa- 724 T H E BELL SYSTEM TECHNICAL JOURNAL, MAY 19G1 S E M I P E R M A N E N T BINARY I N F O R M A T I O N STORED IN T H E F O R M OF T R A N S P A R E N T A N D OPAQUE SPOTS ON P H O T O G R A P H I C PLATES V X