Method of correcting geometrical distortions on the screen of a cathode-ray tube

摘要

Picture tubes with an extremely flat screen exhibit peculiar geometrical distortions in that the beginning and end of the lines in the picture bend symmetrical to the midline as the result of the magnetic deflection field typical of that type of tube. These distortions, called "bending errors," are eliminated in accordance with the invention by coupling another current into the vertical-deflection winding. A current that increases until the horizontal flyback begins is generated 5 to 10 microseconds before the electron beam ends its horizontal forward sweep and an additional current that decreases for 5 to 10 microseconds during the horizontal forward sweep is generated at the end of the horizontal flyback. Eliminating geometrical distortions on the screen of a picture tube.