Granted Patent
Utility
US 4,281,855 · App. 06/051,556
Pressure-sensitive or heat-sensitive recording material and novel 2,2-diarylchromeno compounds used therein
Inventor:
Jean C. Petitpierre
Patented Case
View Patent ↗
Granted: Aug 4, 1981
Filed: Jun 25, 1979
Inventor
Jean C. Petitpierre
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.