White-light generation using a remote-phosphor-coated diffusing surface excited by the high-brightness blue light-emitting diode

Abstract

White-light generation by cerium-doped yttrium aluminum garnet inorganic phosphor, which was used to coat a diffusing polyethylene terephthalate (PET) substrate excited by a blue light-emitting diode (LED) is reported. The diffused PET substrate was used to scatter the directional light of the blue LED at a large angle while the phosphor layer was used to convert the blue light to white light through the downconversion mechanism. The diffuser is color-tunable, which can be achieved by varying the phosphor concentration and the thickness of the coating material. The Commission International de l'Eclairage (CIE) coordinates and the correlated color temperature for the white-light emission were calculated, and the results are reported herein. It was found that the white-light source had the CIE coordinates (0.33, 0.34) and had a broad spectrum profile.