Granted Patent
Utility
US 4,857,721 · App. 07/174,059
Optical direction sensor having gray code mask spaced from a plurality of interdigitated detectors
Inventors:
David S. Dunavan, Rene Abreu, Stephen Messelt, Edward T. Siebert
Patented Case
View Patent ↗
Granted: Aug 15, 1989
Filed: Mar 28, 1988
Inventors
David S. Dunavan
Rene Abreu
Stephen Messelt
Edward T. Siebert
Assignee (at issue)
PerkinElmer, 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.