Granted Patent
Utility
US 4,474,441 · App. 06/204,045
Method and apparatus for controlling exposure by selective use of blocking visible filter
Inventor:
John B. Millard
Patented Case
View Patent ↗
Granted: Oct 2, 1984
Filed: Nov 4, 1980
Inventor
John B. Millard
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.