在具有水平锚定的扭曲相液晶盒中沿表面法线加一外电场. 此外电场可产生3种指向矢形变: (1)均匀形变, 在这一形变中, 指向矢只沿垂直于表面的坐标轴变化; (2)周期性形变, 在这一形变中指向矢沿表面某一轴呈周期性变化; (3)平面内扭曲, 液晶螺旋轴从平行于表面法线方向, 旋转90°至平行于表面. 计算了这3种形变的电场域值, 并获得相图. 结果表明平面内扭曲形变的产生主要由于是弱锚定边界条件, 并与液晶的螺旋性有关. 降低锚定强度, 可使系统从均匀形变相或周期性形变相进入平面内扭曲形变相. 周期性形变相和均匀形变相之间的相变主要由系统的弹性系数和螺距决定. 在螺距较大时, 周期性形变出现在较小的弹性系数比K11/K22.
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