Abstract: An input screen scintillator for an X-ray image intensifier tube. The tube includes light conductive cesium iodide needles formed on an electrically conductive substrate. Each needle is entirely coated with a material such as a metal or a semiconductor which reflects the light travelling within the needle toward the inside of the needle. This coating can enhance the efficiency and resolution of the image intensifier tube.

Abstract: An image intensifying tube, such as a image intensifying tube which converts X-rays into a visible image, comprises a curved input screen which comprises a substrate that receives input radiation and a photocathode supported on the substrate, and an output screen which converts the electrons emitted by the photocathode into a visible image. In order to compensate for changes in luminosity due to the curvature of the input screen, an intermediary layer of radially variable thickness is deposited between the substrate and the photocathode. The intermediary layer is made from a material, such as indium oxide (In.sub.2 O.sub.3), which modifies the electron emitting characteristics of the photocathode as a function of the thickness the intermediary layer. Thus, a thicker intermediary layer near the center of the input screen will compensate for reduced luminosity at the edges of the screen.

Abstract: An input screen for radiological image intensifier tube that includes a scintillator (12), deposited on an aluminum substrate (10), which converts incident X-photons into visible photons which then go on to excite a photocathode (16). Previously, the luminous photons produced by the scintillator were emitted towards and were reflected by the aluminum layer; but this reflection reduces the resolution. According to the invention, in order to suppress this reflection, an input screen--in which a thin layer (20), transparent or slightly absorbent to the wavelengths emitted by the scintillator and or size to cause an anti-reflecting effect--is interposed between the aluminum substrate and the scintillator. Choices of anti-reflecting slightly absorbent layer include indium oxide, or alternatively antimony, tin or bismuth oxide, or a combination of these oxides, such as indium-tin oxide. The thickness is from a few hundred to a few thousand angstroms.

Abstract: The invention concerns an input screen scintillator for an X-ray image intensifier tube. This tube comprises light-conductive cesium iodide needles formed on an electrically conductive substrate. According to the invention, each needle is entirely coated with a material such as a metal or a semiconductor which reflects the light travelling within the needles and allows an identical potential level in the coating material as in the substrate towards the inside of said needles. The coating can enhance the efficiency and resolution of image intensifier tubes. The invention has applications in the field of X-ray imagery.