Temperature-Dependent Degradation of AC Powder EL

It has long been known that ac powder electroluminescent (ACPEL) devices degrade during moderate or high luminance operation. However, the understanding of the degradation mechanism is quite incomplete, although it is believed that the degradation is a diffusion-related phenomenon. To investigate the effect of operating temperature on the lifetimes, ACPEL lamps are tested at various temperatures, ranging from −67 to 49°C in this paper. It is shown that the lamps operated at room temperature or elevated temperature degrade much faster than those at low temperatures. As a result, two diffusion mechanisms are suggested to explain the temperature dependence of the electroluminescence lamp degradation.