Flicker Suppression of AC Driven White LED by Yellow Persistent Phosphor of Ce³⁺–Cr³⁺ Co-doped Garnet

Abstract

The alternative current driven light emitting diode (AC-LED) lighting system has attracted a great deal of attention because of the high luminous efficiency and the simple electric circuit. However, this system causes the unacceptable flicker due to rapid fluctuations in the voltage of the power supply. In order to compensate the flicker effect in AC-LED, we proposed the use of yellow persistent luminescent garnet phosphors. The time evolution of luminescence intensity measurement of Ce³⁺ and Cr³⁺ co-doped Gd₃Al₂Ga₃O₁₂ phosphor using a modulated blue laser diode was performed. From this measurement, the flicker percent of Ce³⁺ and Cr³⁺ co-doped Gd₃Al₂Ga₃O₁₂ phosphor is calculated and showed to be about 60%. This result demonstrated that persistent phosphor is expected to solve the problem of flicker caused in AC-driven LED lighting system.