Granted Patent
Utility
US 4,314,752 · App. 06/182,070
Mount device of a focal length changing auxiliary lens
Inventors:
Sunao Ishizaka, Toshiaki Hozumi
Patented Case
View Patent ↗
Granted: Feb 9, 1982
Filed: Aug 28, 1980
Inventors
Sunao Ishizaka
Toshiaki Hozumi
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.