A packaged light emitting device includes a substrate, a solid state light emitting device on the substrate, a first generally toroidal lens on the substrate and defining a cavity relative to the solid state light emitting device and having a first index of refraction, and a second lens at least partially...http://www.google.com/patents/US7952115?utm_source=gb-gplus-sharePatent US7952115 - Packaged light emitting devices including multiple index lenses and methods of fabricating the same
