We propose an optical configuration to compensate dispersion characteristics in the dark state of a normally-black twisted-nematic (NB-TN) liquid crystal display (LCD). By optimization of parameters with a parameter space diagram (PSD), the high contrast-ratio (CR) over 500: 1 could be obtained using two +A plates. Furthermore, excellent dispersion characteristics were also obtained in the bright state. We confirmed the performance of the proposed method and structure through both the numerical calculations and the experiments.