Granted Patent
Utility
US 4,880,896 · App. 07/191,604
Polycarbonate for disc substrate having low bisphenol content
Inventors:
Kazunari Otsubo, Motonobu Ezoe, Hideo Ago, Koji Yamamoto
Patented Case
View Patent ↗
Granted: Nov 14, 1989
Filed: May 9, 1988
Inventors
Kazunari Otsubo
Motonobu Ezoe
Hideo Ago
Koji Yamamoto
Assignee (at issue)
Idemitsu Petrochemical Co., 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.