Granted Patent
Utility
US 4,770,975 · App. 07/135,893
Optical recording medium
Inventors:
Sumio Hirose, Hiroshi Ozawa, Kenji Abe, Yoichi Hosono
Patented Case
View Patent ↗
Granted: Sep 13, 1988
Filed: Dec 21, 1987
Inventors
Sumio Hirose
Hiroshi Ozawa
Kenji Abe
Yoichi Hosono
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.