Granted Patent
Utility
US 4,380,807 · App. 06/266,901
Echo recognition system
Inventor:
John M. Reynard
Patented Case
View Patent ↗
Granted: Apr 19, 1983
Filed: May 26, 1981
Inventor
John M. Reynard
Assignee (at issue)
Polaroid 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.