Abstract: Picture display device comprising a display tube with an electron gun having a hollow tubular structure with an inner surface on which a resistance structure of a material having a high electrical resistance is provided, which structure constitutes a focusing lens. The resistance structure is connected to at least two axially spaced electric contacts for connecting an anode voltage and at least one electric contact located in between for applying a focusing voltage. An electrode means of low-ohmic material for controlling the focusing lens by means of a dynamic correction signal is arranged in the region of the connection for the focusing voltage. Upon energization, the low-ohmic electrode means particularly exercises a non-rotationally symmetrical effect on the electron beam.

Abstract: A display tube comprising an electron gun having a beam-shaping part and a focusing structure. The focusing structure comprises an elongate hollow structure with a high-ohmic resistive layer provided on the inner and/or outer surface and comprises means for forming a non-rotationally symmetrical lens element in the area of the focusing structure. This may be a structure generating an electric multipole (for example, dipole or quadrupole) which may be incorporated particularly in the high-ohmic resistive layer.

Abstract: Cathode ray tube having an electron gun positioned in the neck portion, the gun comprising a beam-forming part and a focusing structure and the beam-forming part comprising at least a cathode and a metal electrode plate provided with a central aperture, and the focusing structure comprising a hollow tube of an electrically insulating material with inner and outer surfaces and with a layer of high-ohmic resistive material on at least one of the surfaces. The electrodes of the beam-forming part of the electron gun are secured via metal pins to rods for forming an assembly. The hollow tube is directly secured to the metal electrode plate for the purpose of correct alignment. The tube has a first and a second end face, the first end face in one embodiment having a metal plate with a coaxial aperture, and the said metal plate is fixedly connected to the metal electrode plate of the beam-shaping part of the electron gun in such a way that their apertures are coaxial.