Granted Patent
Utility
US 4,810,882 · App. 07/164,258
Mass spectrometer for positive and negative ions
Inventor:
Robert Harold Bateman
Patented Case
View Patent ↗
Granted: Mar 7, 1989
Filed: Mar 4, 1988
Inventor
Robert Harold Bateman
Assignee (at issue)
VG Instruments Group 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.