Abstract: Display tube including a convergence correction device which comprises a plurality of correction coils having coplanar axes and being arranged around the tube neck. The coils are of the planar type. More specifically, there are two sets of four coils for generating two differently oriented four-pole fields and two sets of six coils for generating two differently oriented six-pole fields, while all these coils are arranged on one flexible support which is wound around the tube neck a number of times, for example, one set of coils for each turn.

Abstract: A display device having a pattern of conductors recessed on an electrode, thus reducing the risk of the pattern of conductors being damaged such as from a surface scratch. When the pattern of conductors and the plate are separated from each other by an insulating layer, the pattern of conductors screens the insulating layer from the electron beam. The method is characterized in that grooves are formed between the apertures, and an insulating layer and conducting layer are provided on the walls of the apertures and the grooves.

Abstract: An electron tube device comprising an electron tube having a line cathode, and an electric power source for supplying power pulses to the line cathode. The electron tube device comprises determination means for determining, during a power pulse, the value of a physical quantity which depends on the temperature of the line cathode, comparison means for comparing the value with a reference value and for supplying a control signal, and termination means to end the power pulse in dependence on the control signal. Consequently, the temperature of the line cathode is more stable.

Abstract: A display device having in an evacuated envelope a mechanically tensed thermionic linear wire cathode 4 and a bent first electrode 5 having a slit 6. The wire cathode 4 is rendered insensitive to microphonics by means of positioning means 22 which are urged against the slit 6 by the wire cathode 4.

Abstract: A color display tube which comprises a display window and a phosphor pattern provided on the display window, an emission system for producing a pattern of juxtaposed rows of electron beams correlated with the phosphor pattern, an array of strip-shaped deflection electrodes situated between the emission system and the display screen for deflecting electron beams, each deflection electrode extending between adjacent rows of the emission pattern, alternate deflection electrodes being a commonly connected first group, and the remaining deflection electrodes being a commonly connected second group, is characterized in that the deflection electrodes extend asymmetrically with respect to the rows of electron beams.

Abstract: A method of manufacturing a cathode ray tube which comprises an envelope portion (1) having a longitudinal axis (8) and a gun assembly (32) having a longitudinal axis (8), in which:a. the envelope portion (1) is fixed in an assembly device (30,31) in a given position,b. the gun assembly (32) is provided in the envelope portion (1), the axes (8) substantially coinciding,c. the location and/or the orientation of the gun assembly (32) is adjusted with respect to the axis of the envelope (1), andd. the gun assembly is secured in the envelope. The adjustment of step c is carried out by means of a structure (15), connected to the gun assembly (32), which consists of magnetically half hard material and is magnetized as a multipole, and by means of a device having magnetic field-sensitive sensors (20, 21, 22, 23) provided around the envelope (1) at the level of the structure (15).

Abstract: A method of manufacturing a cathode ray tube in which magnetic poles are provided in or around the neck (4) of the envelope (1) and around the paths of the electron beams extending substantially parallel to the axis (8) of the tube, said poles generating a permanent multipole magnetic field to correct the occurring errors of convergence and color purity and frame defects of the color display tube, which magnetic poles are formed by magnetizing a configuration (17) of magnetizable material which is provided around the paths of the electron beams, which configuration is magnetized by energizing a multipole coil unit (15) by means of a combination of currents with which a static multipole magnetic field is generated and the magnetization is produced by means of a decaying alternating magnetic field which is generated by means of an alternating field coil (16) and which initially drives the magnetizable material on both sides of the hysteresis curve into saturation.