Granted Patent
Utility
US 4,867,522 · App. 07/174,793
Wavelength sensitive optical devices
Inventor:
Stephen A. Cassidy
Patented Case
View Patent ↗
Granted: Sep 19, 1989
Filed: Mar 21, 1988
Inventor
Stephen A. Cassidy
Assignee (at issue)
BRITISH TELECOMMUNICATIONS public limited company
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.