Granted Patent
Utility
US 4,887,878 · App. 07/247,940
Optical modulation device
Inventors:
William C. Robinson, Norman A. Sanford
Patented Case
View Patent ↗
Granted: Dec 19, 1989
Filed: Sep 22, 1988
Inventors
William C. Robinson
Norman A. Sanford
Assignee (at issue)
Polaroid Corporation
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.