Abstract: A deflection unit for a color television picture tube having in the neck thereof an electron gun system for producing a central electron beam coplanar with two outer electron beams. The deflection unit comprises a system of line deflection coils and a system of field deflection coils. The gun end of the system of field deflection coils is provided with two plate-shaped elements of a soft-magnetic material located at a distance from each other in the circumferential direction of the neck of the tube. Such elements are movable in that direction from a neutral position in which the distances between the centers thereof and the outer beams are equal, to a position in which one of such distances is greater than the other in order to correct picture balance errors due to unequal deflection of the beams.

Abstract: Deflection unit (5) in which field-conducting elements (9,10) are provided between the field deflection coil (8) and the line deflection coil (7) so that a good level of astigmatism as well as an acceptably small coma error and a reduced EW frame distortion are obtained. In order to prevent that the field-conducting elements (9,10) from having a detrimental influence on the ten-pole field generated by the field deflection coil (8), each of the said elements is formed as a slightly curved plate having a central portion (15) on which two limbs (17,19) extending substantially transversely to the axis (Z) of the annular member (6) are formed.

Abstract: A color display tube having three electron guns situated in one plane for emitting three electron beams towards a display screen and having a deflection device which is mounted around a neck portion of the display tube and has a deflection yoke comprising: an annular core of a magnetizable material on which a field deflection coil toroidally is wound in such manner that its turns are located in planes passing through the longitudinal axis of the annular core. A dipolar field is generated in combination with a sixpole field resulting in a pin-cushion shaped overall field. To change the field at the rear end from the core from pin-cushion to barrel shape on the inside of the rear end of the annular core members of a magnetically permeable material are provided symmetrically with respect to the axis of the field deflection field.