Granted Patent
Utility
US 4,950,754 · App. 07/467,623
Chromogenic dicyanomethylenepyrazolinones
Inventors:
Hans Junek, Manfred Klade
Patented Case
View Patent ↗
Granted: Aug 21, 1990
Filed: Jan 19, 1990
Inventors
Hans Junek
Manfred Klade
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.