Granted Patent
Utility
US 4,880,990 · App. 07/205,932
Optical liquid-level sensing apparatus
Inventor:
Joseph D. Rando
Patented Case
View Patent ↗
Granted: Nov 14, 1989
Filed: Jun 13, 1988
Inventor
Joseph D. Rando
Assignee (at issue)
IMO Industries 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.