Thomson-csf

Thompson-csf

Jean P Galves

Jean Sagnard

Daniel Gibilini

Jean C Boit

Pierre Merloz

Disclosed is a high luminance color screen for cathode tubes, comprising two fluorescence luminophors of different colors, the visible trace of which, under the effect of electron bombardment, has a color which can be adjusted by the acceleration voltage of the beam of said electrons. Said voltage is variable, during operation, between two extreme values V.sub.o and V.sub.1, in which the two luminophors are arranged on the transparent support of said screen is superimposed layers formed by powders of crystals of each of the said luminophors, separated from one another by plane faces. Said screen is characterized mainly by the fact that the barrier with plane faces comprises a first layer of silicon dioxide, a layer of zinc sulfide and a second layer of silicon dioxide, the layer of zinc sulphide being included between the two layers of silicon dioxide.

High luminance color screen for cathode ray tube and method for making a

An apparatus and method for obtaining a memory function in picture intensifier or amplifier tubes by providing such tubes with an output screen formed of an electroluminescent cell. This cell emits visible light rays when an electric voltage is applied between its surfaces, and possesses hysteresis properties. When voltage is applied to the screen, the picture sent by the electron beam is stored, and re-established when desired, for a given period. The invention can be applied to radiology.

Picture intensifier tube with memorization

The luminescent screen comprises blocks having an optical transparency of less than 1. The blocks are placed between the grains of the first layer of luminescent material and the transparent substrate and have a cross-sectional area which is equal at a maximum to that of the grains. Said blocks are formed by means of a selective plasma etching operation in which the grains of the first layer of luminescent material are employed as a mask.

Luminescent screen and a method of fabrication of said screen

For improving the contrast of information displayed on the screen, there is placed in front of this latter a filter comprising a matrix of channels pierced in a photosensitive glass plate. The pierced plate is covered over the whole of its surface with a blackened deposit so as to reduce to the maximum its coefficient of reflection. Thus filters can be formed readily on request, according to the direction of observation in particular, with a good coefficient of transmission and improved contrast.

Directional filter for a display screen, the method for manufacturing

In order to avoid losses in definition and contrast which are observed in image-converter tubes as a consequence of the light scatter taking place within the body of the scintillators of the input screens of these tubes, when said scintillators occur in the form of a continuous layer of material, the present invention provides for the formation within a layer of microscopic channels which are transversely disposed, the channels being formed by covering the substrate, prior to the deposition of the scintillator thereon, with a layer of a granular material, preferably glass balls. Application to radiology and scintillography.

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Paris, France

Jean P Galves