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:
Dec. 24, 1991
Filed:
Sep. 13, 1989
Robert W Schumacher, Woodland Hills, CA (US);
Robert L Poeschel, Thousand Oaks, CA (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
A hollow cathode capable of self-heating by back ion bombardment to a thermionic emission temperature axially discharges therefrom an ionized plasma of an ambient gas such as xenon. Electrons are axially or radially extractable from the plasma by an anode. A voltage is applied to a keeper electrode disposed between the cathode and anode to sustain plasma discharge of the gas between the cathode and keeper electrode. A control electrode is disposed between the keeper electrode and the anode. Application of a positive voltage (relative to the cathode) to the control electrode causes the plasma discharge to extend from the cathode to the anode, thus closing the switch. Application of a negative control electrode voltage, or simply returning the control electrode to cathode potential, causes the plasma discharge to retract back to the area of the keeper electrode, thereby opening the switch.