Granted Patent
Utility
US 4,241,992 · App. 06/081,972
Recorded image detection system for updatable microfilm
Inventors:
John R. Flint, Heinz E. Hertel
Patented Case
View Patent ↗
Granted: Dec 30, 1980
Filed: Oct 4, 1979
Inventors
John R. Flint
Heinz E. Hertel
Assignee (at issue)
Bell and Howell, LLC
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.