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. 15, 1988
Filed:
Mar. 27, 1987
Applicant:
Inventors:
Juergen Frosien, Ottobrunn, DE;
Erich Plies, Munich, DE;
Assignee:
Siemens Aktiengesellschaft, Berlin and Munich, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
2503 / ; 2503 / ; 250310 ; 250305 ;
Abstract
An electrostatic-magnetic lens is provided having either a symmetrical or asymmetrical magnetic lens which is overlaid with an electrostatic immersion lens. One electrode of the immersion lens is formed as a hollow cylinder, which is within an upper pole piece of the magnetic lens concentrically relative to the axis of symmetry thereof and extending into the region of the pole piece gap. The lower pole piece of the magnetic lens is preferably at a ground potential and clad with the beam guiding tube for protection against contamination and forming the lower electrode of the electrostatic immersion lens.