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. 20, 2001
Filed:
Dec. 10, 1998
Marcellinus P. C. M. Krijn, Eindhoven, NL;
Karel Diederick Van Der Mast, Portland, OR (US);
Philips Electron Optics B.V., Eindhoven, NL;
Abstract
Electron-optical rotationally symmetrical lenses inevitably suffer from spherical aberration which often imposes a limit on the resolution. This lens defect cannot be eliminated by compensation by means of rotationally symmetrical fields. In order to enhance the resolution nevertheless, it has already been proposed to correct the spherical aberration by means of a correction device provided with two hexapoles (,) and two rotationally symmetrical transmission lens systems (,). Each transmission lens system in the known correction device consists of two lenses. According to the invention, one or both transmission lens systems can be replaced by a single lens without reducing the corrective capacity (when only one system,is replaced) or while reducing it only slightly (when both systems,are replaced).