Abstract:
A display device including an electron tube for image reproduction comprising an electron source having a substantially flat emissive surface and comprising a display screen discrete points of which are caused to luminesce by electrons impacting upon a luminescent substance. The selection of the points to be caused to luminesce is performed with the aid of two grids arranged between the electron source and the display screen, each of which have non-intersecting electrodes, a so-called cross-bar. The surface of at least one grid facing the electron source is provided with an insulating or poorly conductive plate having closely adjacent, substantially parallel, narrow passages. The passages have conductive surfaces. The surface of the plate in which the passages are opening out and on which no grid is provided is covered with an electrically conductive layer. The passages are, in particular, secondary-emissive.
Abstract:
A cathode-ray tube, in particular a shadow mask colour tube, having at least one electron gun which comprises at least three grids. The second grid serves as an accelerating electrode. An astigmatic lens element is present in the region of the second and the third grid. As a result of this an elongate spot is formed on the picture display screen of an electron beam in the case of low beam current, while the spot remains substantially unchanged in the case of high beam current. This is of importance, inter alia, for removing moire patterns in a shadow mask colour tube without it being necessary to choose a particular distance of the mask holes.
Abstract:
A gas-discharge picture-display panel comprising a plurality of gas-discharge tubes. The gas-discharge tubes are closed on one side by a window. An electrode is arranged at each end of each gas-discharge tube. The length of the gas-discharge tubes is at least twice the dimension normal to the directions of length and the wall of the tube is coated with a phosphor material. A positive column is formed in the gas-discharge tubes and the ultra-violet radiation produced thereby causes the phosphor to luminesce. A device which reduces the ignition voltage of the positive column is connected in series with the gas-discharge tubes. The device produces either a glow discharge or a plasma to reduce the ignition voltage.
Abstract:
Gas discharge display device of a cross-bar type which comprises a cathode system, an auxiliary anode system and an anode system and in which in order to permit the use of low-dissipation control circuits the electrodes of the auxiliary anode system are at right angles to those of the anode system.