Element with variable optical properties, for use e.g. in back-projection screens operating by transmission, comprises an electrically operated system with variable light diffusion, e.g. a liquid crystal system, and light-absorbing elements

摘要

An element with variable optical properties (I) based on (a) an electrically operated system with variable light diffusion based on optical valve or liquid crystal systems, a system with particles in suspension or a holographic or thermotropic system (a') also incorporates (b) element(s) showing light absorption, at least in the visible range.