James M. Lafferty

Development of Concact Materials for Vacuum Interrupters

Conventional contact materials cannot simultaneously meet three of the most critical functional requirements of the high capacity vacuum interrupter. This paper describes the development of a new class of vacuum interrupter contact alloys which offer exceptional properties combining high interrupting capability, high dielectric strength, and anti-welding. The mechanism by which anti-welding is achieved is described and substantiated by test results.

Beam Deflection Color Television Picture Tubes

The fundamental principles of color-switching at the screen by retarding or accelerating fields with a single electron beam are described. A mathematical analysis is made showing the effects and importance of various voltage and geometric parameters. The focusing effects of the apertures and the uniform fields are fully investigated. A new method of aperture-mask-voltage modulation is given for the accelerating-field case. Single gun tubes using these beam-deflection principles have the advantages of automatic color registry, simple monochrome presentation, short physical length, low color-switching electrode capacitance, and equal numbers of each of the three-color elements. Tubes using the retarding field are advantageous for large size screens, but ones using the accelerating field make much more efficient use of the electron beam. A method of computing aperture positions to give uniform variation in spacings is described. Some of the techniques described in the construction of 16- and 24-inch reflection-type tubes include prevention of microphonics in the screen; printing methods that make webbing lines invisible; glass spacer blocks that withstand high voltage gradients; a method of etching slits in the screen at an angle to reduce beam-current interception; screen alloys that withstand high-power dissipation; and a high-current electron gun.