Granted Patent
Utility
US 4,379,968 · App. 06/220,130
Photo-optical keyboard having light attenuating means
Inventors:
Richard I. Ely, Edward I. Nelson
Patented Case
View Patent ↗
Granted: Apr 12, 1983
Filed: Dec 24, 1980
Inventors
Richard I. Ely
Edward I. Nelson
Assignee (at issue)
Burroughs, Inc.
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.