Silica dispersed nematics and cholesterics for bistable high resolution displays

Highly dispersed silica forms a rebuildable network in nematics capable of stabilizing domains of different optical properties. Displays with silica dispersed (or filled) nematics can be laser-addressed to a scattering state, allowing high resolution display applications as well as optical data storage. A theory based on nematodynamics identifies the laser writing process as a thermal shock effect and corresponds well with experimental results. With this knowledge, the sensitivity of the material was improved using small amounts of chiral dopants. It is also shown that silica dispersed cholesterics with pitch lengths in the visible range form bistable cholesteric textures (BCT). These filled cholesterics can be laser-addressed to a focal conic transparent state or to a reflecting state, depending on the surface treatment of the cell plates.