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US 4,400,622 AGranted
Electron lens equipment
AssigneesNippon Telegraph & Telephone Public Corporation, Hitachi, Ltd.
InventorsYoshinobu Takeuchi, Katsuhiro Kuroda, Susumu Ozasa
Life of this patent
Estimating the term…
Abstract
An electron lens system wherein at least two coils are arranged in the vicinity of an electron-optical lens and are excited in directions opposite to each other, thereby making it possible to adjust the focal distance of the lens without including a rotation attributed to the electron-optical lens in an electron beam which passes through the lens.
Claims8
An electron lens system comprising:
- electron-optical lens means for generating a magnetic field through which an electron beam is to pass;
- at least two coils which are juxtaposed along an optical axis in the vicinity of said electron-optical lens means, at least one of said coils being disposed within a magnetic field of said electron-optical lens means;
- and
- means for adjusting the focal distance of said electron-optical lens means by exciting said coils in directions opposite to each other so that an electron beam passing through the magnetic field of said electron-optical lens means does not undergo any rotation ascribable to said electron-optical lens means.
1 more element
An electron lens system comprising:
- electron-optical lens means for generating a magnetic field through which an electron beam is to pass;
- and
- means including at least two coils which are juxtaposed along an optical axis of said electron-optical lens means for adjusting the focal distance of said electron-optical lens means by generating additional magnetic fields in opposite directions to one another so that an electron beam passing through the magnetic field of said electron-optical lens means does not undergo any rotation ascribable to said electron-optical lens means;
- At least one of said coils being disposed within the magnetic field of said electron-optical lens means.
1 more element
Dependencies are inferred from the claim text.