Solid state electrochromic light modulator

Claim 1

A solid-state variable transmission electrochromic device comprising, a source of charge compensating ions, an inorganic oxide electrochromic counter electrode film composed of a mixture of at least two oxides with a first of said oxides an oxide of a metal from the group consisting of vanadium and chromium and a second of said oxides an oxide of a different metal from the group consisting of V, Cr, Nb, Ta and Ti which on reduction with the accompanying insertion of said charge compensating ions increases its transmission of light of predetermined wavelength, a primary electrochromic film which on reduction with the accompanying insertion of said charge compensating ions decreases its transmission of light of said predetermined wavelength, an insulating electrolyte film contiguous with and separating said inorganic oxide counter electrode film and said primary electrochromic film for the transport of said charge compensating ions therebetween, first and second electrodes contiguous with said inorganic oxide counter electrode film and said primary electrochromic film respectively and separated by said inorganic oxide counter electrode film, said insulating electrolyte film and said primary electrochromic film, said first and second electrodes being for receiving an electric potential therebetween for producing a current flow such that electrons flow into one of said electrodes and out of the other and said charge compensating ions flow through said insulating electrolyte film from that one of said inorganic oxide counter electrode and said primary electrochromic film being oxidized to that one thereof being reduced for modulating said device between states of minimum and maximum transmission at said predetermined wavelength with the direction of transmission change being determined by the direction of current flow.