Granted Patent
Utility
US 4,544,255 · App. 06/671,064
Focus detector
Inventor:
Ken Utagawa
Patented Case
View Patent ↗
Granted: Oct 1, 1985
Filed: Nov 13, 1984
Inventor
Ken Utagawa
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.