The present invention provides a fluorescence-reddening membrane which is made up of a light-transmittable medium and, dispersed therein, (a) a rhodamine base fluorescence pigment and (b) a fluorescence pigment which has absorptions in the blue region and induces energy transfer to and reabsorptions...http://www.google.com/patents/US6221517?utm_source=gb-gplus-sharePatent US6221517 - Fluorescence-reddening membrane and red-emitting device
