Granted Patent
Utility
US 4,457,618 · App. 06/394,294
Optical system for use in electronic enlarger
Inventor:
William T. Plummer
Patented Case
View Patent ↗
Granted: Jul 3, 1984
Filed: Jul 1, 1982
Inventor
William T. Plummer
Assignee (at issue)
Polaroid Corporation
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.