Granted Patent
Utility
US 5,008,528 · App. 07/380,092
Invertible trackball
Inventor:
Douglas Duchon
Patented Case
View Patent ↗
Granted: Apr 16, 1991
Filed: Jul 14, 1989
Inventor
Douglas Duchon
Assignee (at issue)
Logitech S.A.
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.