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:
Nov. 26, 1996
Filed:
Apr. 10, 1995
Karel D Van Der Mast, Eindhoven, NL;
Pieter Kruit, Delft, NL;
Kars Z Troost, Eindhoven, NL;
Alexander Henstra, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
The focusing device 8 for the primary beam in a scanning electron microscope (SEM) consists in known manner of a combination of a magnetic gap lens 34 and a monopole lens 38. The secondary electrons released from the specimen are detected in accordance with the invention by a detector whose deflection unit 52, or the actual detector 64, 66, is arranged in a field-free space between the gap lens and the monopole lens. This space is rendered field-free by a screening plate 44 arranged underneath the gap lens. In order to achieve a high detector efficiency and a large field of vision, the pole tip of the focusing device 8 is provided with an attraction electrode 42 whose potential is higher than that of the specimen.