Reflective Liquid Crystal Polarization Rotator with Ultraviolet-Polymerizable Liquid Crystal Retardation Film

We demonstrate a reflective liquid crystal (LC) polarization rotator with a UV-polymerizable LC retardation film inside an LC cell. The LC polarization rotator consists of two birefringence layers; one layer is a UV-polymerizable LC film that acts as a quarter-wave plate and the other is a nematic LC layer that acts as an electrically tunable retardation film. The polarization direction of the linearly polarized incident light is found to rotate in a sufficient angular range of 2 pi, depending on the retardation of the electrically tunable LC layer. Additionally, good polarization rotation properties are achieved for an arbitrary polarization direction of the incident light. The influence of the error of the retardation from the designed value on the polarization rotation properties is investigated in detail. The polarization rotation function is found to slightly deteriorate with an increase in the retardation error of the UV-polymerizable LC film, whereas the ellipticity of the output light is sensitively enhanced with an increase in the retardation error of the quarter-wavelength plate. (C) 2013 The Japan Society of Applied Physics