Granted Patent
Utility
US 4,333,920 · App. 06/042,013
Benzalphthalides and broad spectrum sun screens
Inventor:
Donald E. Conner
Patented Case
View Patent ↗
Granted: Jun 8, 1982
Filed: May 24, 1979
Inventor
Donald E. Conner
Assignee (at issue)
Van Dyk & Company 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.