Deflection unit for use in a projection television display tube

Electromagnetic deflection unit for use in a projection television display tube, comprising: a system of line deflection coils having two oppositely located saddle coils with their longitudinal conductor groups which are to be positioned on either side of the longitudinal axis of the display tube. At the screen-sided end the conductor groups of the oppositely located saddle coils are located at a first distance, on one side of the tube axis and on the other side they are located at a second, smaller distance from each other, whereas at the gun-sided end the situation is just the reverse, the distances at the screen-sided end being adjusted to generate a 4-pole component upon energisation of the line deflection coil system, which component renders the raster to be written on the display screen trapezoidal, and the distances at the gun-sided end being adjusted to generate a 4-pole component which is opposite to the 4-pole component generated in the proximity of the screen-sided end.