Granted Patent
Utility
US 4,285,729 · App. 06/101,227
Dense crown optical glass
Inventor:
Shizuo Matsumaru
Patented Case
View Patent ↗
Granted: Aug 25, 1981
Filed: Dec 7, 1979
Inventor
Shizuo Matsumaru
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.