Electrical models of TFT-LCD panels for circuit simulations

Abstract

As thin-film-transistor liquid-crystal-display (TFT-LCD) panels become larger and provide higher resolution, the propagation delay of the row and column lines, the voltage modulation of V-com, and the response time of the liquid crystal affect the display images now more than in the past. It is more important to understand the electrical characteristics of TFT-LCD panels these days. There are several commercial products that simulate the electrical and optical performance of TFT-LCDs. Most of the simulators are made for panel designers. However, this research is for circuit, system, and panel designers. It is made in a SPICE and Cadence environment as a commercial circuit-design tool. For circuit and system designers, it will help to design the circuit around a new driving method. 1 Also, it can be easily modified for every situation. It also gives panel designers design concepts. This paper describes the electrical model of a 15-in. XGA (1024 x 768) TFT-LCD panel. The parasitic resistance and capacitance of the panel are obtained by 3-D simulation of a subpixel. The accuracy of these data is verified by the measured values of an actual panel. 2 The developed panel simulation platform, the equivalent circuit of a 15-in. XGA panel, is simulated by HSPICE. The results of simulation are compared with those of experiment, according to changing the width of the OE signal. The proposed simulation platform for modeling TFT-LCD panels can be especially applied to large-sized LCD TVs. It can help panel and circuit designers to verify their ideas without making actual panels and circuits.