Granted Patent
Utility
US 4,734,488 · App. 07/065,136
Polycarbonate and optical disc substrate
Inventors:
Masayoshi Hasuo, Seiichi Mukai, Hiroshi Urabe, Seiji Yoshida, Masahiro Nukui
Patented Case
View Patent ↗
Granted: Mar 29, 1988
Filed: Jun 25, 1987
Inventors
Masayoshi Hasuo
Seiichi Mukai
Hiroshi Urabe
Seiji Yoshida
Masahiro Nukui
Assignee (at issue)
Mitsubishi Chemical 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.