GB1348204A - Liquid crystal display device including gas cells - Google Patents

Abstract

1348204 Modulating light BURROUGHS CORP 23 March 1972 [5 April 1971] 13733/72 Heading H4F [Also in Divisions G4-G6 and H1] A display panel comprises an array of gas discharge cells and liquid crystal material arranged such that on firing the cells current flows through corresponding portions of the liquid crystal to provide a display. A display device comprises a slotted base-plate. 20; intersecting anode and cathode arrays 40, 50 defining cells 70; an insulating plate 80; a further anode array 100 on or in plate 80 and aligned with the anodes 40; and liquid crystal material 130 between plates 110, 140. Apertures 60, 90 in the cathodes 50 and plate 80 respectively are aligned with anode-cathode intersections. Plate 110 is of resistive carbon impregnated ceramic or vanadium glass or is photoconductive. Plate 140 supports a conductive, transparent film of Au or tin oxide in the form of a continuous layer or a plurality of. strips aligned with the apertures 60. The liquid crystal may be doped to provide a memory effect. The gas discharge cells are filled with A, Ne and/or X and Hg at 20-35 Torr. Potential is applied to all anodes 40 and sequentially to cathodes 50 whereby each column of cells 70 is ignited. Simultaneously applying signals to selected anodes 100 causes glow discharges in associated apertures 60 of each column. Positive potential is applied to film 150 so that current flows to selected apertures 60 through adjacent areas of liquid crystal to form a display. A display is erased by applying a 10 k.c. signal, heat or mechanical vibration across the liquid crystal. If the crystal is not doped the gas cells are repeatedly cammed. In another embodiment electrodes 40 slots in plate 20 and apertures 60 are omitted and electrode 150 replaced by an array of electrode strips 150<SP>1</SP> (Fig. 4, not shown) parallel with electrodes 100 and aligned with cells 90. Grooves in plate 80 provide intercommunication between cells 90 in adjacent rows and columns. Potential is applied to scan rows of cells 90 and current passes through the liquid crystal where electrodes 150<SP>1</SP> are energized. In a further embodiment the plate 110 is of insulating material and rod or pin electrodes extend through it from cells 90 into the liquid crystal. A metal plate or coating with apertures corresponding to apertures 90 may be placed on plate 110, and connected to electrode 150 to concentrate the electric field and improve definition.