Investigation of color shift of plastics lenses in LED-based products

Although color shift is one of the key issues to be considered for the failure of LEDs products, there is limited literature that correlated LED products´ lifetime performance to their color shift over time. This is mainly due to the lack of a suitable model to define the color shift over time. In this paper, a methodology for characterizing and predicting the color shift of the polycarbonate materials in LED products is developed. It had shown that the color shift follows the 1st order reaction. Furthermore, the rate coefficient k of the reaction was found to follow Arrhenius relationship with activation energy of 0.046eV.