Behavioral Model of Patterned Vertical Alignment Pixel in Active-Matrix Liquid Crystal Displays

This paper proposes a more accurate behavioral circuit model to predict transient responses of an active-matrix liquid crystal display (AMLCD) with a patterned vertical alignment (PVA) mode. In the case of the PVA mode, we observed that simulation errors increase when the conventional circuit model is directly applied to overdriven static and dynamic data transitions. To overcome this issue, we investigate the actual behavior of the liquid crystal (LC) molecules in the PVA AMLCD pixel using a high-speed camera attached to a microscope. We discovered that the behavior of the LC molecules is significantly dependent on their proximity to the edges of transparent electrodes. Based on this investigation, we propose a first-order circuit model that has two LC groups with two different response characteristics. The proposed model is embedded in a circuit simulator using an analog hardware description language. Simulation results show that the transient optical responses are considerably more accurate than the conventional responses for any data transitions, including overdriven transitions.