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.

Abstract: Device for assembling an integrated electron gun system 5 for a color display tube of the "in-line" type which is composed of a number of electrodes centered around an axis. The device comprises a centering pins situated with their longitudinal axes substantially in one plane, on which the electrodes are positioned and are then fixed mechanically with respect to each other. If such a device comprises three centering pins (60, 61, 62) which, at least at the area of the apertures in the electrodes, have a substantially elongate perpendicular cross-section so that only selected parts (64, 65) of the centering pins contact the inner wall of the apertures in the electrode, the longitudinal axes of the cross-sections of the outermost pins being substantially perpendicular to the surface and the longitudinal axis of the cross-section of the central centering pin being substantially situated in the plane, the electrode can be positioned more accurately than with the device used up till now.

Abstract: An electron gun system for a three beam color display tube. Slot-shaped openings are provided in the sides of cup-shaped focusing electrodes of the system to facilitate alignment during assembly. The electrodes are stacked on a jig having a pin passing through central electron beam apertures of the respective electrodes. Arms having V-shaped ends are then passed through the slot-shaped openings until they engage collars of the electrodes which define the apertures in the respective electrodes.

Abstract: A color display tube includes in an evacuated envelope, an electron gun system for producing three electron beams directed onto a display window. For each electron beam the electron gun system is provided with a cathode which is secured in a cup-shaped control grid having an aperture. The control grids are secured to a cup-shaped anode by means of a plate of electrically insulating material. The electron gun system may be constructed with a focusing electrode which is common for the three electron beams and a common accelerating electrode. A sleeve-shaped electrode may be secured to the anode and the focusing electrode is secured thereto by means of a ring of electrically insulating material.