DEVELOPMENT OF A SIMULATION TECHNIQUE FOR THIN-FILM-TRANSISTOR LIQUID-CRYSTAL DISPLAYS

For active matrix liquid crystal displays (LCDs) using amorphous silic on thin-film transistors (a-Si TFTs), a novel simulation technique was developed. This simulation technique makes it possible to analyze acc urately the fluctuation in the source voltage of the gate voltage trai ling edge (feedthrough voltage) that is the main cause of image qualit y degradation in the TFT-LCDs; consequently, we can accurately predict the image quality in the TFT-LCDs. The following are the two features : (1) a-Si TFT model considering the intrinsic capacitance which cause s the dependence of the feedthrough voltage on the drain voltage is co nstructed; and (2) an analysis method for the gate voltage waveform di stortion to calculate the difference of the feedthrough voltage betwee n pixels depending on each pixel position in the TFT-LCD has been exte nded from the analysis using an RC delay circuit to a matrix analysis using TFT matrix network. The feedthrough voltage obtained by this sim ulation method agrees with the measurement within 10 percent.