Granted Patent
Utility
US 5,639,809 · App. 08/490,152
Azo compounds and polarizing films using the compounds
Inventors:
Yoriaki Matsuzaki, Ryu Oi, Rihoko Imai, Keisuke Takuma, Hisato Itoh
Patented Case
View Patent ↗
Granted: Jun 17, 1997
Filed: Jun 14, 1995
Inventors
Yoriaki Matsuzaki
Ryu Oi
Rihoko Imai
Keisuke Takuma
Hisato Itoh
Assignee (at issue)
Mitsui Toatsu Chemicals, Incorporated
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.