Granted Patent
Utility
US 4,548,481 · App. 06/549,325
Variable magnification observation optical device
Inventor:
Kenji Yamada
Patented Case
View Patent ↗
Granted: Oct 22, 1985
Filed: Nov 7, 1983
Inventor
Kenji Yamada
Assignee (at issue)
Nippon Kogaku K.K.
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.