Abstract
The main function of backlight modules (BLMs) of thin film transistor liquid crystal displays (TFT-LCDs) is to provide steady and intensive illumination for the whole monitor. Warpage of BLMs can produce non-uniform brightness in TFT-LCDs and result in the so-called Mura effect. In this paper, a warpage inspection system of BLMs was assembled. Experiment was designed to simulate the real working conditions of temperature and humidity, i.e. hygrothermal working conditions, of BLMs. Phase-shifting technique was adopted to improve the resolution of shadow moiré fringes. The surface morphology under different working conditions of BLMs was then obtained and plotted. The out-of-plane displacement fields of BLMs under the same working conditions was also analyzed by the commercially available finite element software ANSYS and compared with the experimental results. Finally, thermal stress distribution of BLMs can be calculated from the modified ANSYS model. © 2009 SPIE.