Granted Patent
Utility
US 5,252,769 · App. 07/905,505
Anthraquinonic colorant and polarizing film containing the colorant
Inventors:
Tsutami Misawa, Hisato Itoh, Tsutomu Nishizawa, Masami Nakano, Hiroyuki Katayama
Patented Case
View Patent ↗
Granted: Oct 12, 1993
Filed: Jun 26, 1992
Inventors
Tsutami Misawa
Hisato Itoh
Tsutomu Nishizawa
Masami Nakano
Hiroyuki Katayama
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.