On chip vacuum fluorescent display drive

Claim 1

A display system comprising: (a) a plurality of displayable characters each being comprised of a respective set of activatable segment electrodes; (b) an electron-emissive member common to all of said displayable characters; (c) a plurality of anode electrodes in cooperative association with said electron-emissive member, each of said anode electrodes being in cooperative association with a respective one of said characters; (d) electrical power supply means for supplying electrical current to said electron-emissive member to electrically heat said member and for providing a predetermined voltage; and (e) means for alternately enabling and disabling the supply of heating current to said electron-emissive member at a predetermined rate in dependence upon the thermal inertia of said member so as to maintain the temperature thereof within a predetermined range and for selectively applying said predetermined voltage between said electron-emissive member and selected ones of said anode electrodes during periods when said current supply to said electron-emissive member is disabled, whereby a visual display is produced at selected character positions associated with said selected ones of said anode electrodes.