Input screen for radiological image intensifier tube utilizing an anti- reflecting layer

摘要

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.