Granted Patent
Utility
US 4,441,175 · App. 06/342,459
Partial beam focus sensing in an optical recording system
Inventor:
Curtis A. Shuman
Patented Case
View Patent ↗
Granted: Apr 3, 1984
Filed: Jan 25, 1982
Inventor
Curtis A. Shuman
Assignee (at issue)
Magnetic Peripherals, 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.