Granted Patent
Utility
US 6,018,421 · App. 08/928,479
Multilayer thin film bandpass filter
Inventor:
David Henry Cushing
Patented Case
View Patent ↗
Granted: Jan 25, 2000
Filed: Sep 12, 1997
Inventor
David Henry Cushing
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.