Polarization eigenvectors for reflective twisted nematic liquid crystal displays

We compare the reflective and transmissive properties (intensity transmission and phase shift) for a twisted nematic liquid crystal display (LCD). Our goal is phase-mostly modulation with a phase shift that exceeds 2 pi rad and the reflective geometry is of interest because the phase modulation depth increases with the double pass. We examine the polarization eigenvectors for two reflective geometries, by including or not including a wave plate between the LCD and the mirror. The LCD behavior is modeled with a simplified physical model that uses two birefringence parameters that depend on the addressed gray level. Experimental results show excellent agreement with theoretical predictions including a large phase modulation depth with an almost flat transmission response. (C) 2001 Society of Photo-Optical Instrumentation Engineers.