Complementarity between fluorescence and reflection in photoluminescent cholesteric liquid crystal devices.

The combination of photoluminescence (PL) and cholesteric liquid crystal (CLC) provides interesting complementary features for an optimized display application. Distortion of the Bragg lattice of CLCs decreases selective reflection but increases fluorescence intensity; recovery of a uniform lattice in turn results in increased reflection and decreased fluorescence. This complementary relationship between the fluorescence and the Bragg reflection gives rise to self-compensations for color shifts due to either dynamic slow response of CLC helix or mismatch of oblique incidence of light with respect to the helical axis. These color shifts have long been intrinsic unsolved limitations of conventional CLC devices. Thus, the complementary coupling between the fluorescence and the CLC Bragg reflections plays an important role in improving the color performance and the quality of moving images.