| 摘要 |
1,129,967. Cathode-ray storage tubes. MARCONI CO. Ltd. 18 March, 1966 [3 Aug., 1965], No. 33235/65. Heading H1D. In a continuously operated direct viewing storage tube, e.g. for surveillance radar, in which image decay or attenuating pulses are applied to the target backing electrode, the flood beam is pulsed to secure persistence times of e.g. 2 minutes or more. The flood beam may be physically cut-off between pulses by reducing the potential of collimating electrodes or by applying a negative potential to a spacecharge grid, or the beam may be effectively cut off by reducing still more the potential of the target backing electrode or by raising the potential of the flood gun cathode and diverting the flood beam to the collector mesh, alternate "on" pulses coinciding with the decay and viewing phases of operation. The E.H.T. applied to the screen of the tube is at a minimum during the decay phase and is at a maximum during the viewing phase. The dutyratio of the pulsed flood beam may be adjustable for brightness control and the decay pulses may comprise trains of pulses differing in duration and amplitude. |
