DEVICE FOR ADJUSTING ELECTRON BEAMS IN A CATHODE-RAY TUBE

摘要

Device for Adjusting Electron Beams in a Cathode-Ray Tube A magnetic ring for adjusting colour purity and convergence is secured to the electron gun of a colour-picture tube. It encloses an oblong area which is perpendicular to the plane defined by the three electron beams produced by the electron gun. The shape of the magnetic ring 22 is chosen so that the y-distance 46 of the ring from the central axis 42.1 of the central electron beam is greater than the distance of the ring from the respective central axis 42.2 of an outer electron beam. This selection of distances influences the focus of the beams. Magnetic rings of this kind can be used in all multibeam cathode-ray tubes and particularly in colourpicture tubes with an electron gun producing three coplanar electron beams.