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:
Feb. 03, 1987
Filed:
Jan. 09, 1985
Yasuyuki Ito, Yokohama, JP;
Toru Sugawara, Fujisawa, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An ion source apparatus comprising a bulk type thermionic cathode, which, when heated, emits thermoelectrons; an anode for causing a gas discharge in cooperation with the cathode thereby producing plasma; a grid electrode for extracting ions out of the plasma; a magnetic member for confining the plasma within a prescribed region; and a ferromagnetic body which surrounds the thermionic cathode. The ferromagnetic body removes the lines of magnetic force produced by magnets from the neighborhood of the surface of the thermionic cathode. As a result, thermoelectrons are freely emitted from the thermionic cathode, thereby ensuring a stable gas discharge.