Williamson 1957
David Theodore Nelson Williamson, Edinburgh, Scotland assigned rights to Ferranti Ltd., London. Peter James Walker of Huntingdon, England. "Electrostatic Loudspeakers"

Williamson 1957

You don't have a pdf plugin, but you can download the pdf file.   

Filed: September 12, 1957
U.S. Patent 3,008,014
Granted: November 7, 1961

David Theodore Nelson Williamson, Edinburgh, Scotland assigned rights to Ferranti Ltd., London. Peter James Walker of Huntingdon, England.
"Electrostatic Loudspeakers"