Patent ID: 7999992

Claim:
An electrochromic assembly comprising: first and second electrodes, at least one electrode being transparent; a porous flexible polymer membrane defining a plurality of pores, the porous flexible polymer membrane having a first refractive index and located between the electrodes; an electrolyte filling the pores, the electrolyte including an ionic liquid and having a second refractive index substantially matching the first refractive index, the electrolyte and membrane together forming a substantially transparent electrolytic layer; a first electrochromic layer covering at least part of the first electrode; and a second electrochromic layer covering at least part of the second of the electrode, the first electrochromic layer having an absorption spectrum which is complementary to the absorption spectrum of the second electrochromic layer, wherein the spacing between the first and second electrodes is held substantially constant by the porous flexible polymer membrane.