Fluorescent display device

Claim 1

In a fluorescent display device having at least a filamentary cathode for emitting electrons, a plurality of pattern display sections each composed of a plurality of anodes each coated with a fluorescent material layer, a plurality of control electrodes electrically independent of one another provided opposite to said pattern display sections respectively, said anodes and control electrodes being selectively given drive signals thereby to make the electrons emitted from said filamentary cathode impinge on said anodes so as to display characters, numerals, graphic forms and the like on said pattern display sections, the improvement which comprises a plurality of auxiliary electrodes provided at or above and in the vicinity of gaps between said control electrodes respectively and at all times kept at a positive potential with respect to said filamentary cathode; said positively charged auxiliary electrodes shaping an electric field formed above said anodes in order to make said electrons emitted from said filamentary cathode impinge uniformly on the entire surface area of said selected anodes to thereby prevent display defects, to produce uniform light emission for a clear fluorescent display and to decrease the space between said pattern display sections; said auxiliary electrodes being supported above and in the vicinity of said gaps by at least two conductive support members that are located perpendicular to said gaps and said auxiliary electrodes; and said auxiliary electrodes being spaced above and in the vicinity of said gaps by at least two insulating spacers that are located perpendicular to said gaps and said auxiliary electrodes; said at least two insulating spacers separating said at least two conductive support members from said control electrodes.