DE3118998

A self-converging deflection yoke having toroidally-wound vertical deflection coils incorporates a pair of magnetically permeable field formers mounted on either side of the yoke. The field formers shunt a portion of the external field flux to the vicinity of the electron gun assembly where they form a pincushion-shaped field which aids in vertical coma correction. In one embodiment, a yoke comprising planar-wound vertical coils incorporates both coma-correcting rear field formers and a pair of front crossarm assemblies for providing side-pincushion correction. The resultant yoke provides covergence of electron beams free of coma and side-pincushion distortion with reduced sensitivity to transverse motion. In another embodiment, similar results are obtained without the front crossarms by vertical deflection coil having a nonradial winding configuration.