Granted Patent
Utility
US 4,873,169 · App. 07/087,599
Process for the preparation of an o-naphthoquinonediazide sulfonic acid ester and photosensitive mixture containing same
Inventors:
Fritz Erdmann, Horst-Dieter Thamm, Hans J. Staudt
Patented Case
View Patent ↗
Granted: Oct 10, 1989
Filed: Aug 20, 1987
Inventors
Fritz Erdmann
Horst-Dieter Thamm
Hans J. Staudt
Assignee (at issue)
Hoechst GmbH
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.