Photonic-crystal full-colour displays

In our information-rich world, it is becoming increasingly important to develop technologies capable of displaying dynamic and changeable data, for reasons ranging from valuea-dded advertising to environmental sustainability. There is an intense drive at the moment towards paper-like displays, devices having a high reflectivity and contrast to provide viewability in a variety of environments, particularly in sunlight where emissive or backlit devices perform very poorly. The list of possible technologies is extensive, including electrophoretic, cholesteric liquid crystalline, electrochromic, electrodewetting, interferometric and more. Despite tremendous advances, the key drawback of all these existing display options relates to colour. As soon as an RGB ( red, green and blue) colour filter or spatially modulated colour scheme is implemented, substantial light losses are inevitable even if the intrinsic reflectivity of the material is very good.