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:
Sep. 22, 1998
Filed:
Nov. 27, 1996
Katsushige Tsuno, Tokyo, JP;
JEOL Ltd., Tokyo, JP;
Abstract
An omega-type energy filter of the B-type in which a beam of charged-particles is focused three times in a direction perpendicular to the direction of magnetic fields and twice in the direction of the magnetic fields. The geometry is so designed that this B-type produces smaller aberrations and larger energy dispersion than the A-type. The filter has four sector magnets M.sub.1, M.sub.2, M.sub.3, and M.sub.4 for successively deflecting the charged-particle beam passed through an entrance aperture and for directing the beam toward an exit slit. The entrance aperture and the exit slit are arranged symmetrically with respect to a central, symmetrical plane. The sector magnets M.sub.1 and M.sub.4 are arranged symmetrically with respect to the symmetrical plane. The sector magnets M.sub.2 and M.sub.3 are arranged symmetrically with respect to the symmetrical plane. The entrance aperture and the entrance face of the sector magnet M.sub.1 are separated by a distance of L.sub.5. The exit face of the sector magnet M.sub.4 and the exit slit are separated by the same distance of L.sub.5. Relations given by ##EQU1## are satisfied.