GB610398A - Electron discharge device - Google Patents

Abstract

610,398. Electron beam apparatus. WESTERN ELECTRIC CO., Inc. April 26, 1946, No. 12674. Convention date, May 2, 1945. [Class 39 (i)] In a high-speed switching device, an electron beam is arranged to scan a row of targets and an auxiliary electrode is provided to enable the targets to be impacted in certain sequences. In Fig. 2, 13 are the target electrodes and 14 the auxiliary electrodes; the latter is shown in detail in Fig. 3. The electrode 14 is secondary electron emitting and is therefore positively charged when impinged on by the beam; since the electrode is connected to the deflecting electrode 16 this positive charge will deflect the beam downwards in the Figure. There is an equilibrium position, a, b, c, d, e, under each finger 21 of electrode 14 for the electron beam; if it rises higher, the deflecting plate 16 is charged and the beam deflected downwards again; if it falls lower, 16 discharges through resistance 18 and the beam is deflected upwards again. Normally, the beam falls on the line O-O, Fig. 3; on the application of a suitable pulse to deflecting plates 24, 25, the beam moves over to the line X-X; 16 then starts charging until the beam takes up the equilibrium position f. When the pulse ends the beam returns to the line O-O and takes up position e. If a pulse of opposite polarity is now applied, the beam moves to the line Y-Y, 16 discharges and the beam takes up the position e<1>; when the pulse ends, the beam moves to d. The beam can thus be made to move upwards in steps, and can at any time be returned to e by a pulse sufficient to move the beam to X-X; alternatively, the beam can be returned to d by a pulse deflecting the beam on to 20B. When the beam is at a, b, c, d, e, the corresponding targets 13A, 13B, &c. are imparted. Thus, the targets can be scanned in several different sequences according to the pulses applied to 24, 25. In a modification, Fig. 4 (not shown), there are diagonal strips across the fingers 21a which enable the beam to be moved down by steps, as well as up, thus increasing the possible number of sequencies obtainable. In a further modification, Fig. 6 (not shown), an additional strip is placed under the upper finger 21a so that the beam is automatically returned to e after reaching a. Stepping speeds of 10 kcs./sec. are said to be obtainable.