Granted Patent
Utility
US 4,947,254 · App. 07/345,057
Layered mix effects switcher architecture
Inventors:
John Abt, Richard S. Bannister
Patented Case
View Patent ↗
Granted: Aug 7, 1990
Filed: Apr 27, 1989
Inventors
John Abt
Richard S. Bannister
Assignee (at issue)
GRASS VALLEY LIMITED
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.