An illumination light source includes four different types of LEDs, namely a blue light-emitting diode 11 emitting blue light, a blue-green light-emitting diode 12 emitting blue-green light, an orange light-emitting diode 13 emitting orange light and a red light-emitting diode 14 emitting red light....http://www.google.es/patents/US6817735?utm_source=gb-gplus-sharePatente US6817735 - Illumination light source
