Granted Patent
Utility
US 4,421,539 · App. 06/292,676
Method of producing rod-shaped base material for optical transmission fiber
Inventors:
Tadao Edahiro, Kazuaki Yoshida, Kunio Ogura, Seiji Shibuya, Hiroshi Murata
Patented Case
View Patent ↗
Granted: Dec 20, 1983
Filed: Aug 13, 1981
Inventors
Tadao Edahiro
Kazuaki Yoshida
Kunio Ogura
Seiji Shibuya
Hiroshi Murata
Assignees (at issue)
Nippon Telegraph and Telephone Public Corporation
FURUKAWA ELECTRIC CO., LTD.
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.