Granted Patent
Utility
US 4,999,306 · App. 07/188,414
Composition, apparatus and method for sensing ionic components
Inventors:
Masao Yafuso, Henry K. Hui
Patented Case
View Patent ↗
Granted: Mar 12, 1991
Filed: Apr 28, 1988
Inventors
Masao Yafuso
Henry K. Hui
Assignee (at issue)
Minnesota Mining and Manufacturing Company
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.