Patent GB-1358571-A (GB)
Title: Segment display panel with cathode groups
Inventor: KUPSKY G A
IPC: H01J17/49
Filed: 1971-07-27
Abstract: 1358571 Gas discharge display panels BURROUGHS CORP 27 July 1971 [6 Aug 1970 9 Nov 1970 14 Dec 1970 15 March 1971 16 March 1971] 35155/71 Heading H1D A gaseous discharge display device comprising an elongated envelope formed of a top plate 100, a bottom plate 20 and a spacer member 74, includes a plurality of groups of cathode segments 60A-60G formed on an insulating layer 40 and connected through apertures 50A-50G in said layer to conductive leads 30A-30G, corresponding segments in each group being connected to the same leads, an anode 70 for each group of cathodes, and means for suppressing "crosstalk" between adjacent display positions. The latter means may be a specified spacing between an anode and its associated and adjacent cathode groups or a conductive shield member between adjacent cathode groups, which shield member may be a side wall of an anode or may be a conductive strip connected to a suitable potential. The cathodes 60 may be formed by a silk-screen process with a conductive paste including palladium, platinum, silver or mixtures of these, or may be discrete strips of metal, e.g. stainless steel, secured to the strips 30 by goldgermanium brazing material or by welding. A ring or mesh filled with a phosphor may be mounted on each cathode (Figs. 6 and 7, not shown) to modify the colour of the display. Alternatively the cathodes may be coated with mercury to resist sputtering. The strips 30 which have conductive leads 34 may be formed by depositing films of gold or tin oxide on the glass or ceramic plate 20. Alternatively the strips may be thin sheets of stainless steel secured to the plate 20. The anodes 70 which have connecting leads 90 may be flat mesh screens supported on an insulating frame 74 or may be open-sided boxes resting on the plate 65 with the leads 90 resting on the frame 74. In an alternative embodiment (Figs. 8 and 9, not shown) the anodes are films of gold or tin oxide formed on the lower surface of the glass cover-plate 100. Conductive strips are provided on plate 100 between adjacent anodes and on the surface of insulating layer 65 between adjacent groups of cathodes. In a further alternative embodiment (Figs. 15 and 16, not shown) the base-plate 20 is a sheet of metal coated with a layer of glass or ceramic, and the apertures in the plate 65 are enlarged to form display cells surrounding the cathodes. The wall of each cell may be coated with a phosphor material including barium as a source of priming electrons. Alternatively, priming may be effected by an auxiliary cell or by a system of slots connecting the display cells, the auxiliary cell or slots containing a continuously energized anode and cathode. Each group of cathodes in this embodiment includes two additional vertical cathodes to represent numeral "one", making nine cathodes in each group, so there are nine strips 30. The additional vertical cathodes may overlap the top and bottom horizontal cathodes to increase the length of the numeral "one", in which case they are made entirely or partially in mesh form. In a further modification (Fig. 20, not shown) the insulating layer 40 is replaced by discrete apertured areas of insulating material. The ionizable gas filling may be neon, argon or xenon or a mixture of two or more of these with mercury vapour added to minimize cathode sputtering. The mercury may be introduced from a glass capsule held in a filling tubulation secured to plate 20 (Fig. 23, not shown). The pressure may be from 20 to 350 torr, preferably 60 to 80 torr.