The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 16, 1988
Filed:
Mar. 20, 1986
Johnny W van der Velden, Heerlen, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
An x-ray image intensifier including an input screen 3 having a radiation transparent support 7 on which is applied a fluorescence layer 8 of CsI, a translucent conductive barrier layer 9 which replenishes the photocathode 10 with electrons but tends to reflect incident light especially when made of metal, e.g. of aluminum 7 nm thick which reflects about 50% of the incident fluorescence. The improvement adds first and second intermediate layers 21, 22 of metal oxide e.g. respectively TiO.sub.2, MnO, which are semiconductive. The thickness of the first layer 21 adjusts the reflection amplitude to equal that at the photocathode-vacuum interface, and that of the second layer adjusts the relative phase so that the reflections cancel. The first and second layers can be non-conductors such as Al.sub.2 O.sub.3, however the second layer is then made thin enough, e.g. 25 nm or less, to allow electron conduction by tunnelling to occur.