Granted Patent
Utility
US 5,817,832 · App. 08/664,271
Blue diketopyrrolopyrrole pigments
Inventors:
Olof Wallquist, Bernd Lamatsch, Thomas Ruch
Patented Case
View Patent ↗
Granted: Oct 6, 1998
Filed: Jun 11, 1996
Inventors
Olof Wallquist
Bernd Lamatsch
Thomas Ruch
Assignee (at issue)
Ciba Specialty Chemicals Corporation
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.