| 摘要 |
1523793 Gas discharge display panels INTERNATIONAL BUSINESS MACHINES CORP 30 Sept 1975 [4 Dec 1974] 39873/75 Heading H1D [Also in Division G5] In an alternating current gas discharge display panel, Fig 3, having opposed sets of orthogonally disposed conductors, H, V, to which an alternating sustain voltage pulse of predetermined amplitude and duration is applied to sustain an ionized condition in the lightemitting cells defined thereby, the sustain voltage is produced from a voltage controlled oscillator 24 whose frequency is controlled in response to the amplitude of the sustain voltage sensed by sensor 25 or 26 and the oscillator 24 is connected to control logic 23 which accordingly sets the frequency of the sustain voltage generated, whereby the sustain voltage frequency is shifted as a direct function of the sustain voltage drift from its predetermined setting. As shown in Fig. 2, the sustain voltage amplitude Vs, which is initially set at 10 in the middle of the window formed between the curves 11, 12 defining the sustain voltage window and which may drift to 13, e.g. due to ageing of the circuits, is returned closer to the centre of the window at 13<SP>1</SP> by altering the sustain voltage frequency appropriately. The control logic 23 to do this is empirically determined for each type of panel manufactured. |
