Generation mechanism of residual direct current voltagein a liquid crystal display and its evaluation parametersrelated to liquid crystal and alignment layer materials

• Published in: Journal of applied physics Vol. 102; no. 1; pp. 014904 - 014904-6
• Main Authors: Mizusaki, Masanobu, Miyashita, Tetsuya, Uchida, Tatsuo, Yamada, Yuichiro, Ishii, Yutaka, Mizushima, Shigeaki
• Format: Journal Article
• Published: American Institute of Physics 06.07.2007
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.2752147

The presence of ionic charges in a liquid crystal layer causes the generation of residual direct current (dc) voltage ( V rdc ) in a liquid crystal cell. V rdc is one of the most important factors governing the image quality of liquid crystal displays, because the existence of V rdc causes the image sticking phenomenon. We studied the generation mechanism of V rdc based on a model of the adsorption and desorption of the ionic charges at the interface between the liquid crystal and alignment layer. In this paper, we propose three evaluation parameters, (i) saturated residual dc voltage, (ii) time to reach its saturation state, and (iii) relaxation time during the open circuit state after applying the external dc voltage, for effective evaluation of liquid crystal and alignment layer materials from the viewpoint of the improvement of the image sticking.