Quantified Insights into LED Variability

There is a variation in the characteristics of an LED partly due to variation in the manufacturing process and the sourcing of materials from differing vendors. From a thermal perspective these variations result in differing thermal characteristics such as R
_thJC
(the thermal resistance between chip junction and case) and Z
_th
(the thermal impedance curve). This study seeks to quantify the measured variation of a number of LED part samples and provide insight into the root cause of those variations. Such information would provide additional confidence to a lighting engineer when selecting LEDs, when modelling their thermal behaviour and thus modelling their thermally dependent optical performance.