Granted Patent
Utility
US 5,897,931 · App. 08/649,906
Magnetic disk with boron carbide overcoat layer
Inventors:
Richard H. Ahlert, James K. Howard, Muhammad Inayet Ullah, Richard Donald Umphress
Patented Case
View Patent ↗
Granted: Apr 27, 1999
Filed: May 15, 1996
Inventors
Richard H. Ahlert
James K. Howard
Muhammad Inayet Ullah
Richard Donald Umphress
Assignee (at issue)
International Business Machines 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.