Granted Patent
Utility
US 4,101,302 · App. 05/789,585
Photochromic gradient lenses
Inventors:
David A. Krohn, Emil W. Deeg
Patented Case
View Patent ↗
Granted: Jul 18, 1978
Filed: Apr 21, 1977
Inventors
David A. Krohn
Emil W. Deeg
Assignee (at issue)
American Optical 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.