Granted Patent
Utility
US 4,424,335 · App. 06/399,881
Keratoprosthetic polyurethane
Inventor:
Michael Szycher
Patented Case
View Patent ↗
Granted: Jan 3, 1984
Filed: Jul 19, 1982
Inventor
Michael Szycher
Assignee (at issue)
Thermo Electron GmbH
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.