an led device including an led chip and a lens positioned apart from the chip and coated with a uniform thickness layer of fluorescent phosphor for converting at least some of the radiation emitted by the chip into visible light . positioning the phosphor layer away from the led improves the efficiency of the device and produces more consistent color rendition . the surface area of the lens is preferably at least ten times the surface area of the led chip . for increased efficiency , the reflector and submount can also be coated with phosphor to further reduce internal absorption .