Patent GB-1273595-A (GB)
Title: Glow discharge display systems
IPC: H01J11/00
Filed: 1969-11-14
Abstract: 1,273,595. Matrix displays. BURROUGHS CORP. 14 Nov., 1969 [29 Nov., 1968], No. 55862/69. Heading G5C. A display system includes a glow discharge device comprising an envelope containing a gaseous atmosphere at a pressure capable of sustaining a glow discharge, at least one anode electrode and one cathode electrode in contact with the gas disposed in said envelope, the combination of said gas and said anode electrode and cathode electrode having a characteristic firing voltage, first means 110, 120 for applying a write voltage to said electrodes to produce a glow discharge in the gas between said electrodes, said write voltage having an amplitude greater than that of said characteristic firing voltage, second means 130, 140 for applying short duration repeated sustaining pulses to said electrodes starting after the termination of said write voltage and repeated at spaced intervals thereafter, said sustaining pulses having an amplitude greater than that of said firing voltage and being of sufficient amplitude, duration and repetition rate sufficient to sustain said glow discharge at a perceptible level of light output, current flow, and power dissipation but insufficient to cause arcing, the amplitude, duration and repetition rate of said sustaining pulses being insufficient to produce said glow discharge if said write voltage has not been applied. The display device is preferably a panel 10 (Fig. 1, not shown) as described in Specification (co-pending Application 48298/69) having a plurality of cells 30 with a cross-bar system of addressing electrodes X, Y. The panel is coupled to a data source 100, e.g. a computer and a control module 104 providing a write signal made up of two signals W of equal and opposite polarities from sources 110 and 120 coupled either directly or through currentlimiting resistors 122 to selected X and Y electrodes, and a sustaining signal made up of two pulses S of equal and opposite polarity from sources 130 and 140 which are applied directly to selected X and Y electrodes. Diodes (not shown) are included in all lines to prevent crosstalk. Information is written into the panel by applying S pulses either to selected X and Y lines associated with cells to be turned on or to all X and Y lines, and then applying W pulses to the selected X and Y lines (Figs. 3 and 4, not shown). Alternatively, W pulses may be applied first to selected lines followed by S pulses (Fig. 5, not shown). As a further alternative, S pulses may be used to perform the write operation, by applying S pulses from sources 130-140 to selected X and Y lines or to all lines and then increasing either the repetition rate (Fig. 7, not shown) or the amplitude (Fig. 8, not shown) or the duration of the S pulses on selected lines for a sufficient time to provide a write voltage which causes selected cells to turn on, after which the altered S pulses are returned to their normal state. An auxiliary sweepout technique may also be employed utilizing a D.C. voltage or, preferably, SW pulses which are applied immediately after the S pulses (Fig. 9, not shown). The SW pulses may be used to minimize the sensitivity of OFF cells to spurious turn on, or in conjunction with S pulses to write information into the panel by removing the SW signal from a cell it is wished to fire (Fig. 10, not shown), or to effect erasure (Figs. 11 and 12, not shown).