Abstract: By giving special shapes to the shielding parts in the electrodes of an electron beam generating system for the use with color picture tubes, there is obtained an improvement in the electron optics. In this way there is reduced in particular the twist error and a common sharpness or sharp focus point is obtained. At the same time the structure of the electron beam generating system is simplified by reducing the number of component parts. Instead of each time three rings there are inserted each time one or two parts in the "grid 4" and/or the "grid 3". If, in addition thereto, these parts are made from a soft magnetic material, and quite depending on the given share, additional fieldformers (shunts and/or enhancers) can be omitted.