Behavioral Circuit Model of Active-Matrix Liquid Crystal Display With Charge-Shared Pixel Structure

摘要

This paper proposes a behavioral circuit model to precisely predict optical responses of an active-matrix liquid crystal (LC) display with charge-shared vertical alignment (CS-VA) mode. CS-VA mode consists of two subpixels in one pixel to mitigate the off-axis gamma distortion. We present a new method using overdrive voltages to obtain accurate capacitance versus voltage $(Chbox{--}V)$ characteristics in CS-VA mode. In addition, we present a new technique to obtain transmittance versus voltage $(Thbox{--}V)$ characteristics of the two subpixels by using a high-speed camera with image processing. In addition, we analyze the panel to obtain precise voltage levels after sharing charges. We describe the behavior of the CS-VA LC display (LCD) by using an analog hardware description language, Verilog-A, and we simulate the CS-VA LCD panel by importing the behavioral circuit model in a circuit simulator, Smart-SPICE. The simulation results of the transient optical responses show excellent matches with the measurement ones.