Granted Patent
Utility
US 4,994,713 · App. 07/354,655
Asymmetric unipotential electron beam focusing lens
Inventor:
Hsing-Yao Chen
Patented Case
View Patent ↗
Granted: Feb 19, 1991
Filed: May 19, 1989
Inventor
Hsing-Yao Chen
Assignee (at issue)
Zenith Electronics LLC
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.