Granted Patent
Utility
US 4,189,640 · App. 05/964,059
Quadrupole mass spectrometer
Inventor:
Peter Dawson
Patented Case
View Patent ↗
Granted: Feb 19, 1980
Filed: Nov 27, 1978
Inventor
Peter Dawson
Assignee (at issue)
Canadian Patents and Development 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.