Variable color and transmission coverings

Abstract

Variable transmission covering systems that can be used, for example, to control the amount of light passing through a window in a building. Using transmissive electrophoretic media that can switch between a first and second optical state, the invention can be used to change the color and/or transmissivity of a structure (or structures) that is placed in front of an object. In some embodiments, the variable transmission system can change transmission and color on command.

1 . A system for modulating light transmission, comprising:
 a plurality of variable transmission electrophoretic structures, the structures configured to transition between a first optical transmission state and a second optical transmission state upon receipt of a signal;   a controller configured to send a signal to the plurality of variable transmission structures, thereby causing the plurality of variable transmission structures to transition between the first optical transmission state and the second optical transmission state.   
     
     
         2 . The system of  claim 1 , wherein electrophoretic structures comprise an electrophoretic material including a plurality of electrically charged particles disposed in a fluid and capable of moving through the fluid under the influence of an electric field. 
     
     
         3 . The system of  claim 2 , wherein a portion of the electrically charged particles have a color selected from red, green, blue, cyan, magenta, yellow, and white. 
     
     
         4 . The system of  claim 1 , further comprising a sensor, coupled to the controller, and configured to measure an intensity of light incident on a first side of the variable transmission structures. 
     
     
         5 . The system of  claim 4 , wherein the controller is configured to send the signal to the plurality of variable transmission structures when the intensity of light exceeds a threshold. 
     
     
         6 . The system of  claim 1 , further comprising a power source. 
     
     
         7 . The system of  claim 6 , wherein the power source comprises a photovoltaic cell. 
     
     
         8 . The system of  claim 7 , wherein each of the plurality of variable transmission structures includes a photovoltaic cell providing power to that variable transmission structure. 
     
     
         9 . The system of  claim 1 , wherein the plurality of variable transmission structures and the controller are operatively coupled with a signal wire, and the signal is sent via the wire. 
     
     
         10 . The system of  claim 1 , wherein the plurality of variable transmission structures and the controller are not coupled together with a signal wire, and the signal is sent wirelessly. 
     
     
         11 . The system of  claim 1 , wherein the first or the second optical state transmits greater than 50% of the incident visible light. 
     
     
         12 . The system of  claim 1 , further comprising an opening mechanism, wherein the plurality of variable transmission structures are coupled to the opening mechanism, and the variable transmission structures can be moved collectively between an open and a closed state. 
     
     
         13 . A system for modulating light transmission, comprising:
 a flexible variable transmission electrophoretic structure, the structure configured to transition between a first optical transmission state and a second optical transmission state upon receipt of a signal;   a controller configured to send a signal to the flexible variable transmission structure, thereby causing the flexible variable transmission structure to transition between the first optical transmission state and the second optical transmission state.   
     
     
         14 . The system of  claim 13 , wherein the electrophoretic structure comprises an electrophoretic material including a plurality of electrically charged particles disposed in a fluid and capable of moving through the fluid under the influence of an electric field. 
     
     
         15 . The system of  claim 14 , wherein a portion of the electrically charged particles have a color selected from red, green, blue, cyan, magenta, yellow, and white. 
     
     
         16 . The system of  claim 13 , further comprising a sensor, coupled to the controller, and configured to measure an intensity of light incident on a first side of the flexible variable transmission structure. 
     
     
         17 . The system of  claim 16 , wherein the controller is configured to send the signal to the flexible variable transmission structure when the intensity of light exceeds a threshold. 
     
     
         18 . The system of  claim 13 , further comprising a power source. 
     
     
         19 . The system of  claim 13 , further comprising an opening mechanism, wherein the flexible variable transmission structure is coupled to the opening mechanism, and the flexible variable transmission structure can be moved between an open and a closed state. 
     
     
         20 . A window covering, comprising:
 a plurality of variable color structures that do not contact the window, the structures comprising an electro-optic medium and being configured to transition between a first color state and a second color state upon receipt of a signal;   a controller configured to send a signal to the plurality of variable color structures, thereby causing the plurality of variable transmission structures to transition between the first color state and the second color state.