Granted Patent
Utility
US 4,970,440 · App. 07/256,673
Orientation independent ignitron with grooved cathode
Inventors:
Wilfried O. Eckhardt, Hayden E. Gallagher, Roland G. Fleig
Patented Case
View Patent ↗
Granted: Nov 13, 1990
Filed: Oct 12, 1988
Inventors
Wilfried O. Eckhardt
Hayden E. Gallagher
Roland G. Fleig
Assignee (at issue)
Hughes Aircraft Company
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.