Granted Patent
Utility
US 5,220,036 · App. 07/447,160
Thiolactone dye precursors
Inventor:
Patrick F. King
Patented Case
View Patent ↗
Granted: Jun 15, 1993
Filed: Dec 7, 1989
Inventor
Patrick F. King
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.