Since the invention of TN LCD by Wolfgang Helfrich and Martin Schadt in 1970,it has generated an unprecedented and pervasive impact on portable low-power mobile displays.Nowadays,TFT-TNs have been widely used in notebook PCs and hand-held mobile displays due to high fabrication yield,low cost,low power,thin and light in weight.However,the pretilt angle in a TFT-TN panel not only affects its contrast ratios,view angles,reliability,but also its aperture ratio caused by the light-leakage positions[1] of fringed-field-induced disclination lines within pixels of the TFT-TN panel.Therefore,methods of measurements [2,3] to yield accurate pretilt angles [5] are important for the fabrication of high-reliable modern TFT-TNs with thin cell gaps below the Gooch–Tarry[4] first minimum in transmission for fast response times and wide viewing angles.For the first time,we have developed a simple method [5] based on a new configuration of out-of-plane cell rotation and analyzed our data by extended Jones matrix method[5] to obtain accurate pretilt angles for such thin TN cells where the published well-accepted configuration of out-of-plane cell rotation method used and analyzed by Birecki and Kahn [3] was insufficient to address.