Abstract: A luminescent display panel comprises a planar anode assembly comprising luminescent anode segments. A glass cover has peripheral flange portions surrounding a window area. So as to enclose a vacuum space, the flange portions are hermetically sealed to the anode assembly by a frit glass layer together with lead-out conductors arranged along at least one particular flange portion for the anode segments, at least one grid, and at least one hot cathode. A transparent and electroconductive film is formed mainly on an inside surface of the window area. The film may be formed also on the flange portions. If formed, the film portion formed on the particular flange portion should have a higher electric resistance than the electroconductive film portion. For example, the resistances should be 10 M.OMEGA. or more between two adjacent lead-out conductors for the anode segments, 1 M.OMEGA.

Abstract: A luminescent display panel comprises a substrate assembly comprising a solid insulator substrate and an underlying and an overlying insulator layer successively thereon, a glass cover, and a sealing layer sealing the glass cover and the substrate assembly to enclose a vacuum space where electrodes of the panel are placed. Use is made of a sealing mass for positively eliminating slow leak which otherwise occurs if at least one of the leads for the electrodes interposed between the insulator layers is extended outwardly of the vacuum space continuously along the overlying layer. The sealing mass may comprise that portion of the underlying layer which lies across the sealing layer, with all leads laid directly on the solid substrate at their portions extended across the sealing layer.

Abstract: A multi-digit luminescent display tube comprises a plurality of luminescent anode segment groups. All anode segment groups may be regularly spaced. Alternatively, at least one single anode segment group may be spaced wider from the remaining regularly spaced ones. A grid is interposed between a cathode and each anode segment group and comprises a pair of grid frame members, or rectangular metal rods, transversely of the cathode. Two of the frame members are made wider on both ends of a series of regularly spaced grids than other frame members of the grid series. Both frame members are also made wider for the single anode segment group than the above-mentioned other frame members.

Abstract: A method for producing multi-figure luminescent display tubes comprising a step of baking a frit glass for fixing parts such as grid electrodes and filament supports onto a substrate which is provided with segment electrodes having phosphor layers applied thereon. The baking process is carried out in a non-oxidizing environment and an infrared heater is used prior to baking to eliminate the frit binder.

Abstract: A multi-digit luminescence display tube comprises an anode assembly including a plurality of luminescent anode segments for each digit, a cathode, a plurality of grids disposed between the cathode and the anode segments of the respective digits, structure for supplying first voltages to the grids and to at least a selected one of the anode segments to make the same luminesce, and apparatus for superposing a second voltage on the first voltage supplied to at least a selected one of the grids to suppress luminescence at the anode segments covered thereby. The cathode comprises a common filament for the anode segments of all digits. Structure is provided for rendering the second voltage non-negative without adversely affecting the brightness of the selected anode segment which are not covered by the selected grid.