Granted Patent
Utility
US 5,641,879 · App. 08/530,971
Phthalocyanines substituted by phosphorus-containing groups
Inventors:
Heinz Wolleb, Hanspeter Preiswerk, Beat Schmidhalter, Heinz Spahni
Patented Case
View Patent ↗
Granted: Jun 24, 1997
Filed: Sep 20, 1995
Inventors
Heinz Wolleb
Hanspeter Preiswerk
Beat Schmidhalter
Heinz Spahni
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.