Granted Patent
Utility
US 4,550,228 · App. 06/468,509
Ribbon speaker system
Inventors:
Gary E. Walker, Leo Spiegel, Anthony J. Shuman, James L. Kirtley, Jr.
Patented Case
View Patent ↗
Granted: Oct 29, 1985
Filed: Feb 22, 1983
Inventors
Gary E. Walker
Leo Spiegel
Anthony J. Shuman
James L. Kirtley, Jr.
Assignee (at issue)
Apogee Acoustics, Inc.
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.