Förfarande och anordning för att åstadkomma en jämn ljustäthetsfördelning över en till ett bildrör hörande frontskiva

摘要

Method for driving a picture tube and circuit assembly for executing the method. Video screens of recent construction have a thickness of the glass increasing towards the corners for reasons of mechanical stability, for this reason and because of the differing absorption of the emitted light through the glass, uneven illumination of the video screen results. For even illumination of the video screen a variable correction voltage is superimposed on the voltage difference at the electrodes of the picture tube which determine the beam current synchronously to the deflection of the cathode beam, the level of the correction voltage being automatically adjustable to the thickness of the glass at the respective location of the cathode beam. The drive method can be used for all picture tubes constructed in accordance with the construction principle mentioned.