Granted Patent
Utility
US 4,421,540 · App. 06/329,915
System for producing an optical fiber preform with gas volume control
Inventors:
Motohiro Nakahara, Tetsuo Miyajiri, Naoki Yoshioka, Toru Kuwahara
Patented Case
View Patent ↗
Granted: Dec 20, 1983
Filed: Dec 11, 1981
Inventors
Motohiro Nakahara
Tetsuo Miyajiri
Naoki Yoshioka
Toru Kuwahara
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.