GB701010A - Compositions having lubricating properties - Google Patents

Abstract

701,010. Cathode-ray tubes. WESTERN ELECTRIC CO., Inc. June 15, 1951 [June 20, 1950], No. 14219/51. Class 39(1) [Also in Group XL(c)] A cathode ray storage tube has a target consisting of a plurality of discrete elemental dielectric islands on a conducting plate 19, Fig. 3, over which the beam is scanned and a collector 18 between the storage surface and the beam source collects secondaries emitted by the dielectric islands, the input signal being applied between the beam source and plate 19 and the output signal being taken from collector 18. In one form, Fig. 3, the gun comprises cathode 12, focusing electrodes 13 and decelerating electrodes 14, and the beam is focused by coils and deflected by two sets of further coils (or electrostatically) over a storage target comprising a copper plate 19 with quartz elements 20 deposited on the front surface, for example by evaporation. The elements 20 need not be of regular shape or of uniform distribution. Fine mesh grid 18 collects secondaries emitted by the quartz elements. An electronic switch S1 connected to the cathode maintains it successively at potentials E1, E2, E3 (preferably 45, 75, 75 volts respectively) negative with respect to plate 19 during the erasing, recording and reproducing scanning cycles. Input signals in the form of a binary pulse code are applied to the cathode from source 21. The collector 18 is connected to electronic switch S2 operating in synchronism with S1, and is slightly positive to plate 19. In the erasing interval (switch S1 at position 1) the scanning beam has low energy so the secondary emission ratio of the target element is less than unity and the elements reach cathode potential. In the recording interval (switch S1 at position 2) .the increase in the negative cathode voltage due to E2 plus a negative signal pulse (first binary signal condition) gives the beam sufficient energy to raise the secondary emission ratio to greater than unity so that the element reaches the positive potential of 19 and 18, while when the signal is zero (second binary signal condition) the beam energy is insufficient and the element remains at cathode potential. In reading switch Sl is at position 3 and E3=E2. The electrons returning to collector 18 are thus made up of (a) fast primaries reflected by the target element at cathode potential which pass through grid mesh 18 without being collected and (b) slow secondaries from the positively charged elements which are collected by 18 and form the output. In a modification, Fig. 4 (not shown), the signal pulses are applied to the target plate 19 instead of to the cathode. In this form, to prevent disturbances of the accelerating fields by the signal pulses, a coarse mesh grid may be arranged in front of the target electrode. In modifications, the beam may be focused electrostatically in which case the collector 18 is positioned adjacent to the target surface. A plurality of devices may be connected in parallel with the provision of suitable switching means so that continuous signals may be stored and reproduced. By varying the reproducing interval with respect to the recording interval, bandwidth increase or reduction can be effected.