Granted Patent
Utility
US 5,218,049 · App. 07/482,256
Sheet or film composed of cyclo-olefin polymer
Inventors:
Yohzoh Yamamoto, Takasi Nakagawa
Patented Case
View Patent ↗
Granted: Jun 8, 1993
Filed: Feb 20, 1990
Inventors
Yohzoh Yamamoto
Takasi Nakagawa
Assignee (at issue)
Mitsui Petrochemical Industries, Ltd.
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.