Granted Patent
Utility
US 5,089,134 · App. 07/633,624
Silica glass filter
Inventors:
Kuniko Ando, Koichi Shiraishi, Masaru Shimbo, Shunzo Shimai
Patented Case
View Patent ↗
Granted: Feb 18, 1992
Filed: Dec 26, 1990
Inventors
Kuniko Ando
Koichi Shiraishi
Masaru Shimbo
Shunzo Shimai
Assignee (at issue)
Toshiba Ceramics 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.