Polymer dispersed liquid crystals for high efficiency displays

Abstract

Polymer dispersed liquid crystal (PDLC) films serve as the basis for a variety of high-efficiency electro-optical effects. In the most general sense, as PDLC materials consists of micron-sized domains of a liquid crystal, with the domain size determined by a continuous polymer matrix running through the film. Depending on the choice of liquid crystal and polymer, a variety of electro-optical effects have been demonstrated. Of these effects, scattering and dichroic-based displays are the most advanced, although development of cholesteric and smectic-based PDLC materials is of high interest. The present dominance of twisted nematic (1N) and supertwisted nematic (S1N) displays means that only technologies which offer dear advantages over these standards can progress to commercialization. One of the limitations of TN displays is a poor optical efficiency and limited viewing angle due to the presence of polarizers. PDLC materials, on the other hand, do not require the use of polarizers, and as such can offer advantages of high optical efficiency and wide viewing angles. High optical efficiencies is an attractive feature for many display applications, offering the opportunity to unseat TN in these areas. This paper summarizes recent progress in PDLC materials development, as well as in applications of these materials to projection and direct-view displays.