MEANS AND METHOD FOR BEAM SPOT DISTORTION IN TV PICTURE TUBES

摘要

A television cathode may picture tube has at least one electron gun for generating at least one electron beam for projecting at least one beam spot on the picture imaging screen of the tube. The gun has a plurality of differently electrically charged electrodes having coaxially aligned openings therethrough for the passage of the beam. The electrodes have juxtaposed faces defining at least one gap in Which is established a beam-focusing electrostatic field. The tube is subject to influences which introduce an undesired distortion of the beam spot to the detriment of the quality of the image projected on the screen. The electron gun is characterized by at least one of the electrode faces being mechanically deformed in the opening perimeter to cause the field to be azimuthally asymmetrical about the opening. The mechanical deformation is effective to act on the beam in a sense tending to at least partially compensate for the undesired distortion of the beam spot.