The 2 X 2 Jones matrix and 4 X 4 Mueller matrix methods are used as computational tools for LCD quiescent state optical mode design. Matrices of a general twisted nematic (GTN) LC cell and some basic optical components are given. The transmission or reflection of a GTN cell can be calculated easily by using these matrices. A parameter space approach of designing LCDs is described, by which many GTN optical modes are revealed with information on their transmittance/reflectance, dispersion and also cell gap tolerance. The 4 X 4 Mueller matrix is introduced both as an alternative to the Jones matrix calculation and an efficient tool for investigating GTN cell polarization transformation. A polarization transformation switching scheme is proposed to explain all GTN display operations. New bistable twisted nematic modes are invented by considering horizontal switching of linear polarization preservation modes.
Reflective LCDs (RLCDs) have high brightness and are free from viewing parallax. They also cost less materials to construct and are compatible with existing manufacturing and driving practices. In this paper, a parameter space description of RLCD as a function of polarizer angle, liquid crystal twist angle and birefringence is discussed. It is shown that all published RLCD modes can be depicted in this parameter space, including the twisted-nematic- electrically controlled birefringence (TN-ECB) modes, the hybrid field effect mode, the mixed-mode TN, and the self-compensated TN (SCTN) mode. Additionally we show several new RLCD modes, including the reflective TN (RTN) and the reflective STN (RSTN) which can be obtained from searching the parameter space systematically. All RLCD modes are related by a variation of the 3 LCD parameters. The RTN and RSTN modes have applications to both direct view and projection display systems. Sample RTN and RSTN displays were fabricated. Experimental results show good agreement with theoretical predictions.
A generalized 2 X 2 Jones matrix representation for twisted nematic (TN) and supertwisted nematic (STN) liquid crystal displays (LCDs) at oblique incidence is obtained. It is based on a model of optical reflection and refraction from stacked birefringent plates. Extension of this 2 X 2 Jones matrix to some special cases is also discussed. This generalized Jones matrix can be used to obtain accurate information on the optical properties of TN and STN LCDs. Numerical comparisons of this new method with the exact Berreman 4 X 4 matrix and the extended Jones matrix of Lien are presented. Simulation results indicate that this new approach is more accurate than existing approximations to the full 4 X 4 calculation. The new generalized Jones matrix method is fast, direct, and simple. It is also physically more intuitive.