Multibeam graphic display system utilizing bit mapping memory

Claim 1

A high definition bit-mapped page display system utilizing a shaped beam and aperture comprising: (a) first means for generating shaped electron beams in a cathode ray tube (CRT) wherein said first means further comprise a CRT tube having at least one cathode, and a heater for each cathode, a focusing electrode, an anode, and a CRT screen coated with a material sensitive to electron impingement; a biasing grid for controlling beam strength, said biasing grid split to comprise at least two sections, each section having a small hole for permitting electrons to pass therethrough, the electrons through the holes forming separate beams individually controllable to be scanned across the screen in adjacent raster scan lines and optically combined on the screen in forming each character; an accelerator for accelerating electrons and having an oblong opening for permitting electrons that pass through the holes in said biasing grid to also pass through the oblong opening in said accelerator; shaping means for shaping the emitted electrons to a predetermined shape; and blocking means having an aperture operative for selectively blocking all or a portion of the shaped beam from passing through, with portions of the beam passing through separate portions of the aperture forming adjacent raster scan lines which are optically combined on the screen in forming each character; (b) second means for generating bit patterns for said shaped electron means, said second means being character generators typically comprising read only memories (ROMs), programmable read only memories (PROMs), or erasable programmable read only memories (EPROMs); and, (c) third means coupled to said second and first means for controlling said shaped beams.