Granted Patent
Utility
US 4,582,641 · App. 06/749,072
Compounds of o-(6-hydroxy-3-oxo-3H-thio(seleno)xanthen-9-yl)benzene sulfonic(benzoic) acid useful as photosensitizers
Inventors:
Hans Hansen, Karlheinz Pfoertner
Patented Case
View Patent ↗
Granted: Apr 15, 1986
Filed: Jun 26, 1985
Inventors
Hans Hansen
Karlheinz Pfoertner
Assignee (at issue)
HOFFMANN-LA ROCHE 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.