Granted Patent
Utility
US 6,628,790 · App. 09/649,671
Apparatus for on-ear operation and off-ear operation with two sound reproduction transducers
Inventor:
Erich Klein
Patented Case
View Patent ↗
Granted: Sep 30, 2003
Filed: Aug 28, 2000
Inventor
Erich Klein
Assignee (at issue)
KONINKLIJKE PHILIPS ELECTRONICS NV
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.