Granted Patent
Utility
US 4,420,722 · App. 06/206,715
Testing semiconductor furnaces for heavy metal contamination
Inventor:
Albert A. Todd
Patented Case
View Patent ↗
Granted: Dec 13, 1983
Filed: Nov 14, 1980
Inventor
Albert A. Todd
Assignee (at issue)
RCA Corporation
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.