Granted Patent
Utility
US 4,474,427 · App. 06/036,503
Optical fiber reflective filter
Inventors:
Kenneth O. Hill, Brian S. Kawasaki, Derwyn C. Johnson, Yoshimasa Fujii
Patented Case
View Patent ↗
Granted: Oct 2, 1984
Filed: May 7, 1979
Inventors
Kenneth O. Hill
Brian S. Kawasaki
Derwyn C. Johnson
Yoshimasa Fujii
Assignee (at issue)
Canadian Patents and Development 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.