Granted Patent
Utility
US 4,394,537 · App. 06/272,549
Sound reproduction device
Inventors:
Kenji Shima, Masahiro Hibino
Patented Case
View Patent ↗
Granted: Jul 19, 1983
Filed: Jun 11, 1981
Inventors
Kenji Shima
Masahiro Hibino
Assignee (at issue)
MITSUBISHI ELECTRIC CORPORATION
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.