Electrode configuration for electron beam scanner

Claim 1

In an electron beam scanning device including an electron source, a target member mounted opposite said source, a power source connected between the target member and the electron source for providing an electron accelerating potential therebetween, a plurality of dynode members sandwiched between the electron source and the target member for controlling the flow of electrons therebetween, the electron source the target member and the dynode member being aligned opposite each other, the dynode members each having a plurality of aperture means formed therein for channeling the flow of electrons between the electron source and the target member, the improvement wherein said dynode members each have a plurality of conductive electrodes arranged in a finger pattern on one of the broad surfaces thereof which are insulated from each other and a single conductive electrode covering substantially the entire opposite broad surface thereof, and comprising means for providing a fixed bias potential to each of said single electrodes and means for selectively alternatively applying a first or second potential to each of said finger pattern electrodes, only one of said potentials providing a forward bias with respect to the associated oppositely positioned single electrode.