Granted Patent
Utility
US 5,633,835 · App. 08/197,631
Long term rapid color changing time indicator
Inventors:
David J. Haas, Sandra Haas
Patented Case
View Patent ↗
Granted: May 27, 1997
Filed: Feb 10, 1994
Inventors
David J. Haas
Sandra Haas
Assignee (at issue)
Temtec, 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.