"Rare Earth" refers to Europium Oxide which Sylvania pioneered for use as the red phosphor in color picture tubes. It really changed the way we viewed TV. I had the pleasure of knowing Lee Davenport, who is credited with it's development.
http://en.wikipedia.org/wiki/Lee_Davenport He was also very instrumental in the early development of radar. He was quite a guy and the consummate gentleman. We met because we both had an interest in old cars. It's odd how paths can cross....