The bright-display electron gun, a high-resolution scanning system

The Large-Area Electronic Display equipment developed for the U. S. Army Electronics Research and Development Laboratory by the Electronics Laboratory of the General Electric Company had design objectives that required the development of a high-performance electron-beam scanning system. The recording sensitivity of the thermoplastic tape, coupled with the 20 megahertz maximum signal-frequency, required a high beam-current-density, 4 kv, electron beam. Electron-optical focus-aberrations and deflection-distortions are key factors of this 3000-line raster-scan system. An aberration balance condition is used to remove deflection-distortions. To achieve a satisfactory recording-sensitivity over the entire 50 mm-square writing-format, it is necessary to maintain a uniform spot-shape no greater than two-thirds the 16µ line-to-line spacing.