Granted Patent
Utility
US 4,525,588 · App. 06/502,039
Chromogenic naphtholactams
Inventor:
Rudolf Zink
Patented Case
View Patent ↗
Granted: Jun 25, 1985
Filed: Jun 7, 1983
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.