Granted Patent
Utility
US 4,983,459 · App. 07/503,587
Chemically reacted glass surface
Inventors:
Helmut Franz, George B. Goodwin
Patented Case
View Patent ↗
Granted: Jan 8, 1991
Filed: Apr 3, 1990
Inventors
Helmut Franz
George B. Goodwin
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.