Granted Patent
Utility
US 4,726,646 · App. 06/703,515
Optical switch
Inventors:
Yoshiyasu Tanaka, Sadakazu Ariga, Mituyosi Suzuki, Ayako Sakamoto
Patented Case
View Patent ↗
Granted: Feb 23, 1988
Filed: Feb 20, 1985
Inventors
Yoshiyasu Tanaka
Sadakazu Ariga
Mituyosi Suzuki
Ayako Sakamoto
Assignee (at issue)
E.I. DU PONT DE NEMOURS AND 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.