Granted Patent
Utility
US 4,847,378 · App. 07/188,807
Chromogenic polycyclic azamethines
Inventor:
Rudolf Zink
Patented Case
View Patent ↗
Granted: Jul 11, 1989
Filed: May 2, 1988
Inventor
Rudolf Zink
Assignee (at issue)
Ciba-Geigy
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.