Granted Patent
Utility
US 6,678,381 · App. 09/197,675
Ultra-directional speaker
Inventor:
Koji Manabe
Patented Case
View Patent ↗
Granted: Jan 13, 2004
Filed: Nov 23, 1998
Inventor
Koji Manabe
Assignee (at issue)
NEC CORPORATION
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.