Multibeam cathode ray tube having a common beam limiting aperture therein

Claim 1

An improvement in a cathode ray tube multibeam electron gun having therein a common emission plane, a parallelly related planar arrangement of separate control electrode members defining an array of individual electron beams, at least one acceleratingcollimating electrode plane, a plurality of substantially cylindrical electron lens-forming electrodes, and a terminally oriented spiral accelErator sequentially positioned forward thereof to effect a plurality of sequentially spaced common crossovers of the beams in directing the array of beams to impinge and focus on the cathodoluminescent screen of said tube in a controlled predetermined manner, said electron gun improvement including means for discretely controlling the sizes of the individual beams comprising: a planar beam-limiting electrode member positioned at the area of the first crossover of said plural beams within one of said cylindrical lens-forming electrodes, said beam-limiting electrode having a single aperture oriented substantially axially therein at substantially a point of crossover of the plural beams in said lensing electrodes to uniformly and simultaneously limit the cross-areal size of each beam passing therethrough.