Granted Patent
Utility
US 4,699,473 · App. 06/803,794
Trifluoromethyl substituted spirooxazine photochromic dyes
Inventor:
Nori Y. C. Chu
Patented Case
View Patent ↗
Granted: Oct 13, 1987
Filed: Dec 2, 1985
Inventor
Nori Y. C. Chu
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.