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:
Aug. 26, 2025
Filed:
Nov. 05, 2024
Hitachi, Ltd., Tokyo, JP;
Takeshi Kawasaki, Tokyo, JP;
Tetsuya Akashi, Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In a field emission electron source used in an electron optical device, a tip distal end portion of the field emission electron source includes a needle-shaped shunt having a diameter that is reduced toward a distal end, a substantially spherical protrusion formed at the distal end of the shunt, a coating that covers the shunt and the substantially spherical protrusion, and an opening through which a part of the substantially spherical protrusion is exposed, the shunt and the substantially spherical protrusion are formed by using first metal as a material, the coating is formed by using second metal as a material, and the second metal has a work function larger than a work function of the first metal.