Variable transmittance optical devices

A variable transmittance optical filter comprising:

• a. a first layer comprising a first substantially transparent substrate with a substantially co-planar (SC) electrode system disposed thereon, the SC electrode system made of transparent electrically conductive material and comprising at least one pair of electrically separate electrodes arranged in a substantially co-planar manner on the first substantially transparent substrate, each pair of electrically separate electrodes comprising a first electrode and a second electrode,
• b. a second layer proximate to the first layer and comprising a transition material comprising a compound that is both photochromic and electrochromic, and that darkens in response to a non-electrical stimulus and lightens in response to application of an electric voltage;
• and
• c. an electrical connection system for electrically connecting the SC electrode system to a source of electric voltage.

A method of preparing a variable transmittance optical filter comprising the steps of:

• a. providing a first layer comprising a first substantially transparent substrate, and;
• i. etching into a layer of substantially transparent electrically conductive material disposed thereon a substantially co-planar (SC) electrode system, the SC electrode system comprising at least one pair of electrically separate electrodes arranged in a substantially co-planar manner, each pair of electrically separate electrodes comprising a first electrode and a second electrode;
• or
• ii. printing onto the first substrate a substantially co-planar (SC) electrode system using a conductive ink, the SC electrode system comprising at least one pair of electrically separate electrodes arranged in a substantially co-planar manner, each pair of electrically separate electrodes comprising a first electrode and a second electrode;
• b. disposing a second layer proximate to the SC electrode system, the second layer comprising a transition material comprising a compound that is both photochromic and electrochromic that is capable of dynamically varying the degree of visible light transmittance on application of an electric voltage;
• and
• c. providing an electrical connection system electrically connecting the SC electrode system to a source of electric voltage.