Full Field Characterization of a Twisted Nematic Liquid Crystal Device Using Equivalence Theorem of a Unitary Optical System

Twisted nematic liquid crystal device (TNLCD) is a key optoelectronic device which is currently applied to video display, and the cell parameters of a TNLCD have high correlation with imaging quality and performance of a liquid crystal display. Owing to the limitations of the current measurement techniques, the cell parameters can mostly be evaluated at single point detection. In order to evaluate the entire performance of a liquid crystal display, it is necessary to develop a two-dimensional measurement technique for characterization of a TNLCD. This research project will develop a measurement system which can characterize the various properties of a TNLCD at high speed. In this research project, the proposed method utilizes the equivalence theorem of a unitary optical system to theoretically derive the analytical function relationship between the measuring intensity distribution of the emergent beam and the optical parameters of a TNLCD. Not only the two-dimensional distribution of the cell thickness, pretilt angle, twisted angle and liquid crystal phase retardation of a TNLCD can be measured, but also the equivalent birefringent properties and the eigen-polarization states which propagate in the liquid crystal layer can be analyzed simultaneously. The proposed method has ability on multiple parameters measurement, additionally, the optical setup of the measurement system is very simple and easy to setup, thus can be served as a testing platform for TNLCD manufacturers.

Project ID:PB10207-1804
External Project ID:NSC102-2221-E182-064