Granted Patent
Utility
US 4,970,021 · App. 07/237,419
Phthalocyanine compounds and utility thereof
Inventors:
Masakatsu Nakatsuka, Tsutomu Nishizawa, Takahisa Oguchi, Hisato Itoh, Katashi Enomoto
Patented Case
View Patent ↗
Granted: Nov 13, 1990
Filed: Aug 29, 1988
Inventors
Masakatsu Nakatsuka
Tsutomu Nishizawa
Takahisa Oguchi
Hisato Itoh
Katashi Enomoto
Assignees (at issue)
Mitsui Toatsu Chemicals, Incorporated
YAMAMOTO CHEMICALS, 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.