Granted Patent
Utility
US 4,156,872 · App. 05/898,701
Display element write sensor
Inventor:
Gordon Helwig
Patented Case
View Patent ↗
Granted: May 29, 1979
Filed: Apr 21, 1978
Inventor
Gordon Helwig
Assignee (at issue)
Ferranti-Packard Limited
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.