CCFL Backlight characterization using luminance meter and image analysis.

In this article, we present a method to measure precisely the performances of direct-lit CCFL backlights using a luminance meter and dedicated image analysis software. The array of CCFL tubes alone can be measured directly and the luminance of each tube can be extracted along its main dimension. So, comparison of the different tubes on the same backlight can be made easily and the performances in terms of backlight uniformity improved. The influence of the diffuser sheet can be probed in the same way and the homogeneity of the entire surface of the backlight can be automatically extracted and quantified.