Granted Patent
Utility
US 5,289,547 · App. 07/802,907
Authenticating method
Inventors:
John S. Ligas, Steven Weber
Patented Case
View Patent ↗
Granted: Feb 22, 1994
Filed: Dec 6, 1991
Inventors
John S. Ligas
Steven Weber
Assignee (at issue)
PPG Industries, 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.