Thin, lightweight, foldable thermochromic displays on paper

This article describes an electronic display that is fabricated by patterning electrically conductive wires (heaters) with micron-scale dimensions on one side of a sheet of paper, and thermochromic ink on the opposite side. Passing electrical current through the wires heats the paper and changes the thermochromic ink from colored (black, green, or other colors) to transparent; this change in property reveals the paper underneath the ink—exposing any messages printed on the paper—and serves as the basis for a two-state “shutter” display. This type of display is thin (100 µm), flat, lightweight (the display weighs <20 mg/cm²), can be folded, rolled, twisted, and creased while maintaining function, and ultimately can (if required) be disposed of by incineration. The display is appropriate for applications where information must be presented clearly (usually only once) for little cost (each display costs <$0.10/m² in materials) and where limited electrical power is available.