Pretilt angle measurement of reflective liquid crystal cells by plural wavelengths Stokes parameter method

Abstract

Stokes parameter methods to determine cell parameters such as a pretilt angle, thickness and twist angle in reflective liquid crystal (LC) cells have been developed by measuring Stokes parameters of reflected light at plural wavelengths. The cell thickness can be determined by measuring one-wavelength Stokes parameters including a near-infrared wavelength, and both the cell thickness and twist angle can also be determined by calculating the Stokes parameter at two wavelengths. Furthermore, these cell parameters containing the pretilt angle as well as cell the cell thickness and twist angle can be determined by using Stokes parameters at three wavelengths. These methods can be applied to determine two-dimensional (2D) cell parameter distributions of the reflective LC cell by using a high resolution CCD camera.