Granted Patent
Utility
US 4,270,840 · App. 06/042,649
Glass fibers for optical transmission
Inventors:
Naoya Uchida, Shigeyuki Seikai, Kozo Yoshimura, Toru Yamanishi
Patented Case
View Patent ↗
Granted: Jun 2, 1981
Filed: May 25, 1979
Inventors
Naoya Uchida
Shigeyuki Seikai
Kozo Yoshimura
Toru Yamanishi
Assignees (at issue)
Nippon Telegraph and Telephone Public Corporation
SUMITOMO ELECTRIC INDUSTRIES, 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.