EFFICIENT POLARIZATION CONVERTER FOR PROJECTION DISPLAYS

In the waveguiding limit, a twisted nematic liquid crystal cell behave s as an achromatic polarization rotator. We propose and demonstrate th e application of such a polarization rotator to convert unpolarized li ght into linearly polarized light with almost 100% efficiency. This po larization converter has a 2:1 aspect ratio, which is close to the 16: 9 ratio for modern televisions. It can be used therefore in a projecti on display with polarization-dependent light valves such as a liquid c rystal light valve. Both transmittive and reflective light valves can be used. The temperature dependence of the achromatic polarization rot ator is also studied. (C) 1997 Optical Society of America.