Granted Patent
Utility
US 4,267,640 · App. 06/034,743
System for ascertaining magnetic field direction
Inventor:
Chin Tao Wu
Patented Case
View Patent ↗
Granted: May 19, 1981
Filed: Apr 30, 1979
Inventor
Chin Tao Wu
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.