Granted Patent
Utility
US 4,703,220 · App. 06/381,921
Incandescent lamp with extended filament lifetime
Inventor:
Peter J. Walsh
Patented Case
View Patent ↗
Granted: Oct 27, 1987
Filed: May 26, 1982
Inventor
Peter J. Walsh
Assignee (at issue)
Duro-Test 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.