Design optimization of coil distributions in deflection yoke for color picture tube

A magnetic deflection system, which has both the horizontal and vertical coils, ferrite core, permanent magnet and coma free coils, is analyzed numerically using a volume integral equation type moment method. In this algorithm, the effects of the auxiliary devices such as permanent magnets and coma free coils can be easily considered. After finding the distribution of the magnetic induction inside the tube and electron beams trajectories, the screen characteristics are calculated. Finally the distribution of the horizontal coil is optimized by using an evolution strategy to get the minimum NS distortion and convergence among the red, green and blue beams at the screen.