A blue-pump LED is a phosphor-conversion white LED package which uses a blue LED chip (InGaN die) to pump light into a wavelength converting element (down-converter). The wavelength converting element contains one or more conversion phosphors. It absorbs blue photons form LEDs and produces broad-band yellow light which then mixes blue emission from the blue LED chip to create a spectrum the human eye perceives as white light. Blue-pump LEDs are the highest efficiency white LED packages today.
