Patent ID: 8687258

Claim:
An optical filter capable of transitioning from a light state to a dark state on exposure to UV radiation and from a dark state to a light state with application of an electric voltage, comprising: a) a first and second substantially transparent substrate; b) a first and second electrode disposed on the surface of at least one of the substrates; and c) a switching material disposed between the first and second substrates and in contact with the first and second electrodes, the switching material comprising one or more chromophores having electrochromic and photochromic properties; the one or more chromophores having the general structure of Formula I: wherein: R 1 is independently H or a halogen; R 2 is independently H, a halogen, or both R 2 when taken together form CHâ•CH, or when in polymeric form R 2 is CHâ•CH and forms part of the polymer backbone; R 5 is H.