ELECTROMAGNETIC DEVICE FOR FOCUSING AND DEFLECTING ELECTRON BEAMS

摘要

An electromagnetic device for magnetically focusing and deflecting an electron beam in a television camera tube comprising a vertical deflection coil, a horizontal deflection coil, a ferromagnetic coil and focusing coil. Electrostatic screens are respectively provided on the inner side of the vertical deflection coil and the outer side of the horizontal deflection coil. In order to prevent or substantially reduce interference signals in the focusing coil from the vertical and horizontal deflection coils, which interference is visible in a signal from a camera tube, the focusing coil comprises multifilar windings having the same winding direction and sense. The windings are connected in series such that the magnetic fields produced by each winding are of the same polarity.