Granted Patent
Utility
US 4,398,539 · App. 06/164,830
Extended focus transducer system
Inventor:
Andrew P. Proudian
Patented Case
View Patent ↗
Granted: Aug 16, 1983
Filed: Jun 30, 1980
Inventor
Andrew P. Proudian
Assignee (at issue)
Second Foundation, Inc.
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.