Abstract: A vacuum cleaner, has a housing and a suction motor, arranged in the housing. When in operation, the motor draws in air via a suction opening and discharges the air via at least one outlet opening in the housing. A dust chamber in the housing collects dust entrained by the drawn-in-air when the vacuum cleaner is in operation. An odor filter is arranged in the housing downstream of the dust chamber. The odor filter includes a unit which temporarily prolongs the residence time of air drawn through the odor filter, in the odor filter during an odor suppression cycle.

Abstract: A color display tube having an electron gun system for producing three in-line electron beams. The system includes, in the direction of travel of the beams, a first electrode, a second electrode and a plurality of focusing electrodes, each having apertures for passing the beams. The second electrode includes two spaced-apart plate-shaped members, each having a central and two outer apertures for passing the beams. The apertures in the members for each outer beam are laterally shifted with respect to each other and with respect to a corresponding aperture in the first electrode to direct the outer beams toward convergence with the inner beam.

Abstract: A cathode-ray tube comprising in an evacuated envelope an electron gun for generating at least one electron beam which is focused on a display screen to form a spot and which is deflected in two mutually perpendicular directions so that a raster is written on the display screen. The electron gun comprises a cathode which is centered on an axis, a first grid at some distance therefrom along the axis and a second grid at some distance from the first grid, the first and second grids each having a part which is perpendicular to the axis and which comprises an aperture around the axis. The aperture in the first grid, on the side of the second grid, is elongate in a direction coinciding with one of the deflection directions and, on the side of the cathode, is elongate in a direction perpendicular to the elongate direction of the aperture on the side of the second grid.

Abstract: The spot quality of an electron beam produced by an electron gun in a cathode ray tube is improved by optimizing the dimensions of a beam-forming, apertured electrode arrangement in the gun. This arrangement includes electrodes for forming a cross-over followed by, in the direction of propagation of the electron beam, first and second lens electrodes centered around an axis, for defining an accelerating and prefocusing lens and at least two lens electrodes for defining a main focusing lens. The diameter of the aperture in the second lens electrode is smaller than twice the diameter of the aperture in the first lens electrode, and the effective spacing S-eff between the first and the second lens electrodes is smaller than 1 mm. S-eff is defined as the minimum of the function ##EQU1## where .DELTA.

Abstract: By making the first grid of an electron gun for a cathode-ray tube to extend in the manner of a funnel in such manner that on the side of the second grid the aperture is elongate and mainly a quadrupole lens action is obtained, it is possible to obtain in the corners and at the edge of the display screen a spot which is surrounded by considerably less haze than the known construction having an elongate aperture in the first grid.

Abstract: By deflecting the electron beams before the focusing lenses in an electron gun system for a color display tube towards the tube axis by non-symmetrical lens fields so that they converge on the display screen, it has proved possible to obtain symmetrical focusing lens fields by means of mechanically non-symmetrical electrodes the axes of which are parallel, if the beams enclose a given angle with the gun axes. This enables an easy manufacture of the electrodes and an accurate assembly of the guns. In these guns the focusing of the beams is independent of the convergence.

Abstract: The method according to the invention consists in the determination of data of the convergence errors of a color display tube, data being derived from the said determinations for determining the polarity and the intensity of magnetic poles of a structure. The structure thus obtained generates a static, permanent, multipole magnetic field adapted to the convergence errors occurring, so that the errors are connected.

Abstract: A method for aligning a deflection unit on an in line CRT uses a multipole field generated by the deflection unit. The center beam is turned on and the deflection unit aligned until it makes a single dot pattern on the CRT screen.

Abstract: An in-line CRT features a static convergence means. It has at most two permanent magnets in or around the tube neck before the deflection coils.