Granted Patent
Utility
US 4,657,379 · App. 06/729,970
Photomask and exposure apparatus using the same
Inventor:
Kyoichi Suwa
Patented Case
View Patent ↗
Granted: Apr 14, 1987
Filed: May 3, 1985
Inventor
Kyoichi Suwa
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.