Granted Patent
Utility
US 4,391,127 · App. 06/252,519
Proximity sensor
Inventor:
William E. Hawkins
Patented Case
View Patent ↗
Granted: Jul 5, 1983
Filed: Mar 20, 1981
Inventor
William E. Hawkins
Assignee (at issue)
E.I. DU PONT DE NEMOURS AND 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.