Granted Patent
Utility
US 6,337,409 · App. 08/282,278
Photochromic naphthopyran compounds
Inventors:
Frank J. Hughes, Edward A. Travnicek
Patented Case
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Granted: Jan 8, 2002
Filed: Jul 28, 1994
Inventors
Frank J. Hughes
Edward A. Travnicek
Assignee (at issue)
Vision-Ease Lens
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.