Knowledge-based control for RGB convergence in deflection yoke of CDT

The color display tube used in computer monitors consists of many components. The deflection yoke (DY) among them supplies the vertical and horizontal magnetic fields so that the spatial trajectories of electron beams can be deflected according to the synchronization signals. If the magnetic fields are not correctly formed, color blurring or blooming where the color image on screen may not be clear will occur. It is misconvergence. In the manufacture of the DY, its quality is strictly controlled to achieve the desired convergence. If the misconvergence happens it has to be cured by sticking the ferrite sheets on the inner part of DY. However, the adjustment is not easy because this process requires an expertʹs knowledge and experience. A knowledge-based intelligent controller using a neuro-fuzzy model will be introduced in this paper.