Granted Patent
Utility
US 4,396,683 · App. 06/240,258
Photomask blank provided with a transparent electro-conductive layer
Inventors:
Takashi Hatano, Akira Maruyama, Keiko Hioka
Patented Case
View Patent ↗
Granted: Aug 2, 1983
Filed: Mar 4, 1981
Inventors
Takashi Hatano
Akira Maruyama
Keiko Hioka
Assignee (at issue)
Konishiroku Photo Industry 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.