摘要
Nowadays,solid-state lighting sources based on white lightemitting diodes(LEDs)are extensively replacing the traditional illumination devices(incandescent and fluorescent lamps)due to their unique and appealing properties,such as high efficiency,high brightness,long working lifetime,small size,fast response time and eco-friendliness[1-4].Because of this,white LEDs have permeated deeply into many important sectors,including indoor and outdoor lightings,signals,displays and therapeutic applications.In order to make sure that white LEDs can provide artificial lighting source with good color quality and high vision performance,there are several important figures of merit that are used to characterize white LEDs:color rendering index(CRI),correlated color temperature,luminous efficacy of radiation and luminous efficacy.
