Device for displaying television pictures including a deflection unit therefor

A display tube has an envelope (10) comprising a neck (14). In the neck (14) there is an in-line electron gun (15). A deflection unit which is provided around the envelope (10) comprising a frame deflection coil system (27). The device comprises a neck coil system (50) situated around the neck (14) for generating a magnetic field comprising a dipolar field component for deflection of the electron beams (19, 20, 21) in a (y) direction transverse to the in-line plane, and means for supplying a current (I50) to the neck coil system (50) which is a non-linear function of the frame deflection current (I27) for reducing inner-pincushion raster distortion.