Measurement of the liquid crystal pretilt angle in cells with homogeneous and inhomogeneous liquid crystal director configuration

摘要

Optical and electro-optical methods of liquid crystal (LC) director pretilt angle measurement are described for LC cells with homogeneous and inhomogeneous LC director distribution. The LC pretilt on both LC substrates can have the same or opposite direction. The phase retardation difference of both extraordinary and ordinary polarized rays passing through an LC cell with homogeneous and inhomogeneous LC director distribution has been calculated versus the LC pretilt angle θ_0 on the cell's substrates in the range 0 ≤ θ_0 ≤ 90°. The experimental procedure for phase retardation difference determination by measurement of the LC cell transmission between crossed polarizers for cells with LC tilted alignment is described. The method developed can also be used in optical compensator design.