Granted Patent
Utility
US 4,641,934 · App. 06/533,993
Ophthalmic lens with diffractive power
Inventor:
Michael H. Freeman
Patented Case
View Patent ↗
Granted: Feb 10, 1987
Filed: Sep 20, 1983
Inventor
Michael H. Freeman
Assignee (at issue)
Pilkington PE Limited
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.