Improvement of fast response LC materials by bent-core dopants in optical compensated bend (OCB) mode liquid crystal displays

Abstract

The stabilization of bend configuration in optical compensated bend (OCB) mode cells by doping bent-core molecules was developed in this study. The values of response time (tau) and threshold voltage (V-th) in OCB cells were dependent on not only the concentration but also the shape, dipole direction, and flexible chain length of the doping molecules. Experimental results showed that the total response time (tau(total)) and threshold voltage (V-th) of OCB cells could be reduced by doping bent-core molecules, and smaller tau values by reducing flexible chain lengths as well as smaller V-th values by reducing polarization of bent-core molecules were normally obtained. In general, higher concentrations of dopants normally induced shorter field-on response time (tau(on)) and a minimum field-off response time (tau(off)) occurred at 0.5% of doping concentration, where the fastest total response time (tau(total)) values were achieved.