Granted Patent
Utility
US 4,631,416 · App. 06/564,854
Wafer/mask alignment system using diffraction gratings
Inventor:
William Trutna
Patented Case
View Patent ↗
Granted: Dec 23, 1986
Filed: Dec 19, 1983
Inventor
William Trutna
Assignee (at issue)
Hewlett-Packard Company, L.P.
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.