Granted Patent
Utility
US 4,937,671 · App. 07/290,783
Digital video black expander
Inventor:
Christopher M. Engel
Patented Case
View Patent ↗
Granted: Jun 26, 1990
Filed: Dec 28, 1988
Inventor
Christopher M. Engel
Assignee (at issue)
Zenith Electronics 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.