A broadband wide-incident-angle reflective polarization converter

A high-performance reflective polarization converter which could be used in a backlight recycling system for liquid-crystal-display (LCD) devices is proposed. The device consists of a twisted-nematic (TN) liquid-crystal film, a uniaxial A-plate, and a reflector. The configuration parameters, such as thickness and orientation of the films, are optimized using a genetic algorithm. As a result, the design can convert light from TM to TE polarization (or TE to TM) at a maximum 99.7%, minimum 91.3%, and average 96.7% conversion efficiency for the entire visible spectrum and incident angle from 0 to 60 degrees. Such a broadband reflective polarization converter is particularly useful for enhancing the light efficiency and reducing the power consumption of LCDs