Paperlike Thermochromic Display

A paperlike, thermally activated display has been fabricated by researchers in Hong Kong. The display is flexible, and has the ability to change its colors in a reversible and repeatable manner.

The new technology introduces a new type of flexible displays. Flexible displays are already made by packing liquid crystal in small capsules, each capsule representing one pixel. However, displays designed this way might become very expensive.

The featured display is composed of thermochromic composite that changes its color due to according to temperature, and of embedded conductive wiring patterns. The thermochromic material has accurate and stable characteristics, which prevent the smearing of the displayed image.

In order to change the displayed image, localized heating is used. The heating of the display is supplied by the nano-wiring, manufactured by soft lithography. As seen in the picture, switching the voltage turns a displayed image on and off. Color changes occur as the local temperature rises to 60oC.

The mechanical properties of the display might make it very suitable for commercial applications such as e-books, cellular phones, toys and more. It is only 150 microns thin and can be bended and folded without losing its functionality. Also, since experiments have shown that the display can function even with a very low 0.13W power source, it can run on batteries.

More details about the product and the experiments may be found here (subscription required).

Logo image displayed by switching the voltage.
The functionality is not affected by bending
(Credit: Applied Physics Letters)

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