GB1368815A - Electronic indicia display system - Google Patents

Abstract

1368815 Matrix displays OMRON TATEISI ELECTRONICS CO 23 Nov 1971 [25 Nov 1970] 54387/71 Heading G5C An indicia display system comprises a plurality of gas filled discharge tubes each having a cathode, a plurality of anodes arranged to display indicia and. a grid for controlling electron flow to the anodes, circuits for applying high potentials to selected anodes and to selected grids in response to two pulsed input signals and means for cutting off the beginnings and ends of the anode or grid pulses This prevents more than one digit appearing which would otherwise occur due to the pulses not being perfectly square. Corresponding anodes of each tube are connected in parallel Potentials corresponding to the row of digits to be displayed are successively applied to the anodes and potentials are applied sequentially to each grid to operate each tube only when the appropriate anode signal is applied Square wave generators S, U produce pulses in synchronization with clock pulses CP1 upon receipt of signals from a decoder of an electronic calculator The output from generator S passes via MOS transistors Q 11 ... Q 17 , to which clock pulses are applied, and transistors Q 21 ... Q 27 to transistors TRI ... TR7 which apply pulses to selected anodes by grounding these anodes which are normally at a negative potential. The output from generator U is connected together with timing pulses t 0 to gates A1 ... A3 whose outputs are connected to transistors Q 41 ... Q 43 via transistors Q 31 ... Q 33 to which clock pulses CP2 are also applied. The transistors Q 41 ... Q 43 operate transistors TR11 ... TR13 to apply sequential pulses to the grids. Clock pulses CP1, CP2 are of equal length but 180 degrees out of phase. Pulses t 0 are 3 clock pulses in width and in phase with CP2. The grid pulses are therefore ¥ the length of the anode pulses and because of the phase difference between CP1 and t 0 are centred with respect to the anode pulses i.e. a portion of both the front and rear of the grid pulses has been removed. In another embodiment the output from the generator S is applied directly to the anodes and pulses t 0 replaced by periodic signals from a counter.