Granted Patent
Utility
US 4,618,564 · App. 06/738,197
Process for production of positive images using sulfonic acid precursors
Inventors:
Christopher G. Demmer, Edward Irving
Patented Case
View Patent ↗
Granted: Oct 21, 1986
Filed: May 24, 1985
Inventors
Christopher G. Demmer
Edward Irving
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.