Large scale display panel apparatus

Claim 1

A large scale color display panel capable of displaying an image containing half tones and of varying intensity, comprising: a plurality of light emitting elements, each of said light emitting elements being capable of emitting light in a selected combination of three primary colors, each of said light emitting elements comprising three cathode-ray tubes, each cathode-ray tube comprising at least one fluorescent screen for emitting light of one of said primary colors from substantially an entire front surface thereof and an electron gun for producing an unfocused flood of electrons directed toward said fluorescent screen; a plurality of drive circuits, one of said drive circuits being provided for each said electron gun for turning on and off said electron gun with an on-to-off time ratio determined in accordance with an intensity of light to be emitted by the cathode-ray tube of which said electron gun forms a part, and hence a hue of light to be emitted from the light emitting element of which said cathode-ray tube forms a part; a plurality of memory means, one of said memory means being provided for each said drive circuit for storing a binary control signal representing and on/off state of a corresponding one of said electron guns; and brightness adjusting means coupled to each of said drive circuits for setting a brightness level of light to be emitted by controlling a magnitude of drive of said electron guns.