Granted Patent
Utility
US 5,170,192 · App. 07/619,735
Oxygen permeable bifocal contact lenses and their manufacture
Inventors:
Lisa A. Pettigrew, Donald J. Ratkowski, William J. Burke, Joseph I. Weinschenk, III
Patented Case
View Patent ↗
Granted: Dec 8, 1992
Filed: Nov 29, 1990
Inventors
Lisa A. Pettigrew
Donald J. Ratkowski
William J. Burke
Joseph I. Weinschenk, III
Assignee (at issue)
Pilkington Visioncare Inc.
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.