Granted Patent
Utility
US 4,997,271 · App. 07/416,768
Method of and an apparatus for producing a required visual signal for direct observation from a first source of light in the presence of a second source of light
Inventor:
Ian A. Shanks
Patented Case
View Patent ↗
Granted: Mar 5, 1991
Filed: Oct 4, 1989
Inventor
Ian A. Shanks
Assignee (at issue)
Thorn EMI plc
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.