Effects of nematic liquid crystal doped with multi-walled carbon nanotube on electro-optic properties and electrostatic discharge immunity of liquid crystal display device

Abstract

ABSTRACT Electrostatic discharge is a vexing problem in liquid crystal display device, which can cause abnormal display. Conventional solutions for liquid crystal doped with antistatic agent usually introduce additional impurity ions and increases the power consumption of liquid crystal display device. In this study, multi-walled carbon nanotube doped liquid crystal cells without obvious clusters are successfully fabricated. Comparing the electro-optic properties of undoped and doped cells, it is verified that doping does not negatively affect the liquid crystal cells with E7 host by measuring basic parameters such as relative permittivity, threshold voltage and response time. The liquid crystal cells are then tested using an electrostatic discharge generator to simulate the human-machine air discharge that occurs during actual operation. The immunity of the doped versus undoped cells is quantitatively compared in terms of the duration of so-called image sticking, it is found that the electrostatic discharge immunity of cell has a significant relationship with electrical conductivity. In addition, the relationship between the conductivity and relaxation time of image sticking is obtained by theory. It is determined that doping carbon nanotubes into E7 can effectively improve the electrostatic discharge immunity of liquid crystal display device without negatively affecting practical application.