向列相液晶电流体不稳定性——偏置电场效应

本文考虑了外电场与液晶盒玻璃片法线成倾角θ₀时,沿面排列的向列相液晶(θ_α<0,σ_α>0)的电流体不稳定性现象。在Dubois-Violette等人的一维理论的基础上,我们获得了直流、正弦波和矩形波三种电场激发下的失稳条件。重要结果包括:(1)电荷弛豫时间随θ₀单调上升。(2)对于MBBA液晶,存在一个临界角θ_c(ω)(ω是外场频率),当θ₀>θ_c(ω) 关键词：

ELECTROHYDRODYNAMIC INSTABILITIES OF NEMATIC LIQUID CRYSTALS——EFFECT OF AN INCLINED ELECTRIC FIELD

Electrohydrodynamic instabilities of a planar nematic liquid crystal (ε_α<0,σ_α>0) under an inclined electric field (at an angle θ₀ with the normal of the glass plates of the cell) are considered. On the basis of the one-dimensional theory of Dubois-Violette et al, conditions for the onset of instabilities under the excitation of static, sinusoidal and square wave electric Fields, respectively, are obtained. Major results include: (1) Relaxation time of charge increases monotonically with θ₀. (2) For MBBA, there exists a critical angle θ_c(ω)(ω is frequency of external field), when θ₀> θ_c(ω) instability cannot occur. θ_c(0) =54.2°. (3) For MBBA, threshold voltage is a monotonic increasing function of θ₀.