Granted Patent
Utility
US 6,422,235 · App. 09/674,780
Vocal valve with filter
Inventor:
Jan-Ove Persson
Patented Case
View Patent ↗
Granted: Jul 23, 2002
Filed: Dec 6, 2000
Inventor
Jan-Ove Persson
Assignee (at issue)
Atos Medical AB
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.