Live Colorimeter Calibration Adapts to Spectral Variations of Measurement Object

In principle, all colorimeters need color calibration, because the color filters that are used to mimic the eye’s sensitivity to visible light will never perfectly match the theoretical CIE 1931 functions. Calibration to a standard light source improves measurement accuracy, but especially for most new and often immature display and lighting technologies, e.g. µLED and AR/VR does not provide adequate accuracy.
For example, small variations in µLED current density, temperature and manufacturing tolerances will change the spectral properties and may render the colorimeters calibration invalid. Hence, measurement uncertainty increases. This can lead to erroneous pass/fail decisions in display and LED manufacturing.
Consequently, we developed a measurement device that adapts its calibration on-the-fly in accordance to the “live” spectral changes of the DUT.
We discuss experiments to demonstrate the accuracy and robustness of this concept for displays, LEDs and µLED wafers.