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: The invention relates to a cathode-ray tube 1 having an electron gun 3 positioned in a neck portion 2. The electron gun 3 is provided with a focusing structure 10 which includes a hollow tube 12 of electrically insulating material. A layer 14 of a material having a high resistance is applied to the inner surface of the hollow tube. The resistance layer 14 is shielded from a getter arrangement 44 positioned in the cathode ray tube 1.

Abstract: A method of manufacturing a cathode ray tube which includes an electron gun (3) having a number of electrodes (7, 8) and a resistive-layer lends system (5), characterized in that the electron gun is sparked in a manufacturing step in which a pulse voltage is applied to an electrode (8) and a direct voltage is applied to a part (9) of the resistive-layer lens system adjacent to said electrode (8) through supply leads. During the sparking step measures are taken to prevent the occurrence of sparks in the resistive-layer lens system (5) per se, which in turn prevents damage to the resistive-layer lens system.