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.

Date of Patent:
Feb. 28, 2006

Filed:

Nov. 22, 2004
Applicants:

Mark J. Cattelino, Palo Alto, CA (US);

Fred I. Friedlander, Saratoga, CA (US);

Inventors:

Mark J. Cattelino, Palo Alto, CA (US);

Fred I. Friedlander, Saratoga, CA (US);

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J 29/70 (2006.01);
U.S. Cl.
CPC ...
Abstract

Axially symmetric magnetic fields are provided about the longitudinal axis of each beam of a multi-beam electron beam device. The magnetic field symmetry is independent of beam voltage, beam current and applied magnetic field strength. A flux equalizer assembly is disposed between the cathodes and the anodes and near the cathodes of a multi-beam electron beam device. The assembly includes a ferromagnetic flux plate completely contained within the magnetic focusing circuit of the device. The flux plate includes apertures for each beam of the multi-beam device. A flux equalization gap or gaps are disposed in the flux plate to provide a perturbation in the magnetic field in the flux plate which counters the asymmetry induced by the off-axis position of the beam. The gaps may be implemented in a number of ways all of which have the effect of producing a locally continuously varying reluctance that locally counters the magnetic field asymmetry. The flux equalizer assembly prevents or substantially reduces beam twist and maintains all of the electron beams of the device as linear beams.


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