Granted Patent
Utility
US 4,948,228 · App. 07/239,993
Optical image rotators
Inventor:
Andrew P. Keens
Patented Case
View Patent ↗
Granted: Aug 14, 1990
Filed: Sep 2, 1988
Inventor
Andrew P. Keens
Assignee (at issue)
Thorn EMI plc
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.