Quote Originally Posted by Photo Engineer View Post
I have searched patents, Fred. I have not gotten to RDs or Defensive Publications which are rather harder to access and search. It really does not matter as these fluorescent compounds were complexes of things such as Europium and Yttrium or something like that. I had the information at one time, but I did not want to do any work on it due to the cost.

Presumably some connection with the "rare earth" elements used in things like color tv and mobile phone displays?