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:
Apr. 16, 1991
Filed:
Jan. 08, 1990
Johnny van der Velden, Heerlen, NL;
Theodorus F van Bergen, Heerlen, NL;
August L Simons, Heerlen, NL;
Johannes K Colditz, Heerlen, NL;
Martinus A Ligtenberg, Heerlen, NL;
Franciscus M Dreesen, Heerlen, NL;
U.S. Philips Corp., New York, NY (US);
Abstract
The entrance screen in an X-ray image intensifier includes an intermediate layer of a material which selectively absorbs photon energy. As a result, the speed of the photo-electrons is substantially reduced, thus improving the imaging. By introducing a radial variation of the absorption in the intermediate layer, vignetting-compensation can also be realized without substantial loss of sensitivity and resolution for the central portion of the tube. The resolution at the periphery of the tube can thus be substantially improved.