Granted Patent
Utility
US 4,864,624 · App. 07/175,001
Piezoelectric loudspeaker with thermal protection
Inventor:
Thomas H. Tichy
Patented Case
View Patent ↗
Granted: Sep 5, 1989
Filed: Mar 30, 1988
Inventor
Thomas H. Tichy
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.