Granted Patent
Utility
US 5,693,808 · App. 08/554,214
Process for the preparation of peryleneimides, novel di-, tri- and tetrachromophoric perylene dyes and their use
Inventor:
Heinz Langhals
Patented Case
View Patent ↗
Granted: Dec 2, 1997
Filed: Nov 6, 1995
Inventor
Heinz Langhals
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.