Light intensity behavior of LED lamps within the thermal stabilization period

Abstract

Visible changes in the light intensity of lamps, referred to as flicker, are quantified based on definitions such as normalized gain factor and relative light intensity variation. However, those values also change depending on the time after an LED lamp has been switched on. An experiment has been carried out to analyze this phenomenon. A new metric, a “thermal stabilization time”, has been proposed to identify the time to reach steady state light intensity. Although rare, the change in light intensity can reach up to 68% during the thermal stabilization time. Consequently, acquiring data at different intervals can lead to incorrect estimation of critical metrics. Stabilization is an essential factor that should be taken into consideration in LED lamps' measurement. It is recommended by the authors that 60-minute operation is required before acquiring data.