电场作用下向列相液晶指向矢与流动的耦合机理

Coupling mechanism of electric field induced nematic’s director and backflow

作为开发液晶流动驱动的第一步,运用宏观ELP模型及Frank弹性理论对电场作用下液晶盒内向列相液晶的指向矢旋转与所引起的液晶流动之间的耦合机理进行了理论与实验研究。通过对液晶盒进行施加及撤销电场的操作,得到了液晶盒内瞬间液晶指向矢的旋转及所引起的液晶流动的变化情况。电场施加瞬间指向矢的旋转控制着流动的变化,二者同时达到最大值:指向矢旋转为350(°)/s,引流速度为30μm/s;而电场撤销的瞬间流动的变化控制着指向矢的旋转,流动特征与电场施加瞬间很相似,但持续时间很短。实验验证采用最直接的观察法,用显微镜自带CCD拍摄液晶盒在电场施加和解除过程中内部液晶引流发生的过程,通过图像分析得到实验数据,每个数据点分别通过取10次实验的平均值得到,实验结果与理论计算结果吻合。

Simulated and experimental study of the coupling mechanism of the nematic’s director and backflow under the electric-field are conducted by using the ELP model and the Frank elastic theory,as the fundamental research on the development of liquid crystalline driving and control technology.At the moment the electric-field is applied,the rotation of the directors plays a leading role and the induced backflow is determined by it,the two values reach the maximum at the same time.On the contrary,at the moment the electric-field is released,the rotation of the directors is controlled by the backflow and the tilt angle surpasses 90 deg before returning.The calculation results are in good agreement with the experimental results.