Static convergence adjustment for in-line colour picture tube - has hard magnetic material convergence device repeatedly magnetised inside tube

摘要

The convergence device is made of a hard magnetic material and is mounted inside the tube. It is magnetised by a coil put on the tube neck, so that the three electron beams intersect in the centre of the screen, in the shadow-mask plane. The electron beam is blanked and the convergence device is magnetised. The magnetising current is switched off and at least one electron beam is brightened up and the position of the light spot is registered. The beam is then blanked and the magnetisation is again carried out in accordance with the light spot position. The process is repeated until the three electron beams intersect as required.