METHODS AND APPARATUS FOR IMPROVING CATHODE RAY TUBE IMAGE QUALITY

摘要

A time-varying control signal is developed by a current sensor (68) connecting the imaging screen (22) and a closely proximate screen grid (52) of a cathode ray tube as an imaging electron beam is operatively swept across the screen to produce images thereon. The control signal is processed and then applied to at least one of the tube operating elements - such as the horizontal and vertical deflection coils, the focussing lens (14) and, in a plural beam tube, the convergence assembly (50) - which controls a characteristics affecting the quality of an image.