Browse Prior Art Database

Beam Switching Tube

IP.com Disclosure Number: IPCOM000098912D
Original Publication Date: 1958-Dec-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Barber, AE: AUTHOR [+2]

Abstract

A cathode ray tube having a field emission electron gun, vertical and horizontal deflection plates, and four distinct collecting plates is useful as a logic performing computer element. The tube is a single pole, four position electronic switch having switching speeds of about 0. 1 micro seconds. With this switch tube all sixteen possible binary output functions for two independent inputs X and Y can be obtained. When the voltage on the deflection plates is such as to have the beam of electrons hit plate 11, the condition is defined as X = 0, Y = 0, where X and Y refer to the input horizontal and vertical deflection plates. The output at each of the four plates 11, 12, 21 and 22 is designated by off-on or 0 - 1.

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Beam Switching Tube

A cathode ray tube having a field emission electron gun, vertical and horizontal deflection plates, and four distinct collecting plates is useful as a logic performing computer element. The tube is a single pole, four position electronic switch having switching speeds of about 0. 1 micro seconds. With this switch tube all sixteen possible binary output functions for two independent inputs X and Y can be obtained. When the voltage on the deflection plates is such as to have the beam of electrons hit plate 11, the condition is defined as X = 0, Y = 0, where X and Y refer to the input horizontal and vertical deflection plates. The output at each of the four plates 11, 12, 21 and 22 is designated by off-on or 0 - 1.

The tube has a field emission electron gun rather than a conventionally heated cathode gun for several reasons: (1) field emission facilitates getting a much higher beam current than thermionic emission, (2) field emission electron guns can be made considerably smaller in size and (3) no filament power is required.

The physical size of the tube is of the order of one cubic centimeter. Typical operating conditions are given for a 10 milliampere beam current and 100 volt output swings. Ten or twenty volt input levels are necessary on the deflection plates to switch the beam.

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