A display for 100 million dots on a five-inch face

The paper describes a microspot tube for ultra-high resolution on a large face. With a spot diameter of 8 microns, the tube can scan a square of 8 cm in 10,000 lines, using 42° magnetic deflection. This is equivalent to the display of 100 million dots on a five-inch face. While the beam power at 20 kilovolts is only 30 mw, the power loading on the screen is 60 kilowatts per square centimeter! Vapor deposited, filmed phosphor developed by Dr. D. Cusano have been found to stand up well under these conditions. The electron-optics includes many novel features. One of these is the use of a resistive helix in the neck which effectively doubles the electrical length of the neck. Another is the use of a tiny object aperture (.0005") which is illuminated by over 20 amperes per square centimeter. This enormous intensity is generated by a microgun which uses a matrix cathode at an emission density of only 2 amperes per square centimeter.