Granted Patent
Utility
US 4,816,939 · App. 06/898,527
Magnetic recording media and servo systems using light-transmitting optical gratings
Inventors:
Vernon E. Ford, Jeremy K. Jones, John J. Mader, William T. Plummer
Patented Case
View Patent ↗
Granted: Mar 28, 1989
Filed: Aug 21, 1986
Inventors
Vernon E. Ford
Jeremy K. Jones
John J. Mader
William T. Plummer
Assignee (at issue)
Polaroid 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.