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  • Patent number: 4119883
    Abstract: In a cathode ray tube of the single-gun, plural-beam type in which the plurality of beams are made to intersect each other substantially at the optical center of a main focusing lens, any disparity in the focusing effects imparted to the respective beams by the main focusing lens and any auxiliary lens is corrected by applying suitably different biasing voltages to the cathodes emitting the respective beams so that the beams are subjected to different accelerations and travel through the lens fields at different speeds. Thus, the focusing effects of the lens fields on the respective beams are varied to cause the beams to be precisely focused on the screen. The cathode and control grid electrodes are physically arranged to permit control of the individual beam currents for proper color balance.
    Type: Grant
    Filed: August 1, 1975
    Date of Patent: October 10, 1978
    Assignee: Sony Corporation
    Inventor: Senri Miyaoka