Granted Patent
Utility
US 5,879,592 · App. 08/988,310
Water soluble photochromic compounds, compositions and optical elements comprising the compounds
Inventor:
Anil Kumar
Patented Case
View Patent ↗
Granted: Mar 9, 1999
Filed: Dec 10, 1997
Inventor
Anil Kumar
Assignee (at issue)
PPG Industries, Inc.
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.