Contrast enhancement in double-layered dye-doped polymer-dispersed liquid-crystal cells

In this article, the light transmission process in single- and double-layered polymer-dispersed liquid-crystal (PDLC) cells and its relevance for contrast ratio calculations have been discussed. Double-layered cells consist of two PDLC films with a common central wall. We demonstrate theoretically and experimentally that the contrast ratio of double-layered cells is larger than the one of a single PDLC film, but in general, it is not the product of the contrast ratios of the individual films, contrary to the result obtained neglecting multiple scattered light. The same result holds for a single film working in reflective mode. Our results may be potentially relevant for display applications.