Phosphor-Conversion White Light Emitting Diode Using InGaN Near-Ultraviolet Chip

摘要

We have synthesized a Eu~(2+)-activated Sr_3MgSi_2O_8 blue phosphor and (Sr,Ba)_2SiO_4 yellow phosphor. We fabricated a phosphor-conversion white light emitting diode(LED) using an InGaN chip that emits 400 nm near-ultraviolet(n-UV) light and phosphors that emit in the blue and yellow region. When the white LED was operated at a forward-bias current of 20 mA at room temperature(RT), the color temperature(T_(cp)), average color rendering(R_a), operating voltage(V_f) and luminous efficacy(η_L) were estimated to be 5800K, 72.08, 3.4V, and 7.61 lm/W, respectively. The commission International de I'Eclarirage(CIE) chromaticity coordinates obtained from the measured spectra remained almost constant during the forward-baias current increase from 0.5 mA to 60 mA.