Optical density measurement of thin-film transistor liquid crystal display by a monochrome light-emitting diode

摘要

A new method using a monochromatic light-emitting diode (LED) to measure the optical density (OD) of the black matrix of thin-film transistor liquid crystal display (LCD) is developed in this study. The measured results show that the average OD difference is within 1percent between the proposed 3 W monochromatic LED and the currently adopted 100 W quartz halogen lamp. On the other hand, the monochromatic LED reduces the boosting time by 40percent in establishing the baseline database. The 3sigma standard deviation of the OD of the test samples is from 0.1percent to 0.6percent for the LED, whereas it is from 0.5percent to 1.2percent for the halogen lamp. Using standard glass samples, the monochromatic LED demonstrates accuracy within 1.58percent, better than that of the quartz halogen lamp. Therefore, it can substitute for the quartz halogen lamp currently used in the thin-film transistor LCD industry for OD measurement of the black matrix layer, as it is faster, is more accurate, is more reliable, and consumes less power.