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:
Apr. 13, 1982
Filed:
Apr. 30, 1980
John E Wolfe, Julian, CA (US);
Burroughs Corporation, Detroit, MI (US);
Abstract
Disclosed is an electron-beam cathode which emits electrons in a cone-shaped pattern whose electron density is substantially uniform throughout the cone. The cathode is comprised of a needle-shaped piece of single crystal tungsten having dopant atoms of zirconium and oxygen in the bulk thereof, and having only a single (100) surface on the needle's tip. This cathode is formed by the steps providing a needle-shaped piece of single crystal tungsten having dopant atoms of zirconium and oxygen in the bulk thereof, and having a plurality of ring-shaped (100) surfaces on the needle's tip; and subsequently transforming those surfaces into diagonally oriented planar surfaces by heating the needle in an atmosphere of oxygen to diffuse tungsten atoms from the needle's tip to its sides.