Granted Patent
Utility
US 4,904,507 · App. 07/191,972
Information device
Inventor:
David Greenwood
Patented Case
View Patent ↗
Granted: Feb 27, 1990
Filed: May 9, 1988
Inventor
David Greenwood
Assignee (at issue)
IMPERIAL CHEMICAL INDUSTRIES 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.