Granted Patent
Utility
US 5,041,547 · App. 07/542,286
Chromogenic substituted 4,7-diazaphthalides
Inventors:
Robert E. Miller, Troy E. Hoover
Patented Case
View Patent ↗
Granted: Aug 20, 1991
Filed: Jun 22, 1990
Inventors
Robert E. Miller
Troy E. Hoover
Assignee (at issue)
Appleton Papers Inc.
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.