Granted Patent
Utility
US 5,071,986 · App. 07/621,153
Chromogenic phthalides and azaphthalides
Inventors:
Rox Phaff, Davor Bedekovic
Patented Case
View Patent ↗
Granted: Dec 10, 1991
Filed: Nov 30, 1990
Inventors
Rox Phaff
Davor Bedekovic
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.