Granted Patent
Utility
US 4,440,672 · App. 06/360,455
Photochromic composition resistant to fatigue
Inventor:
Nori Y. C. Chu
Patented Case
View Patent ↗
Granted: Apr 3, 1984
Filed: Mar 22, 1982
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.