Could the next generation touch screen be made from paper?

Japanese researchers Kohei Tsuji and Akira Wakita from Japan's Keio University have invented a touch screen using paper. Using color-changing inks and temperature sensitive inks, the duo has created paper that behaves like plastic touch screens.

Tsuji and Wakita call their invention polychrome paper computing. It involves color-changing inks on one side of a sheet of paper and painted conducting pastes that make an electric circuit on the other side. Touching the paper activates a copper pressure sensor taped on the back of the paper. The sensor sends electricity through the painted silver wires which warms a paste of carbon.

The heat from the carbon will alter the temperature of the inks. The inks are made from liquid crystal and its molecules will organize into twisted helixes when warmed. The material changes color from red to blue to green as the liquid crystal structure changes temperature.

The idea behind the technique is to bring interactivity to paper. This technique is for artists who want to use paper's softness and flexibility but also want to make use of some animation to their work.

Wakita and Tsuji demonstrated their technique at SIGGRAPH in Hong Kong. In one demonstration they printed a butterfly with color-changing ink in its wings. Pressing the center of the butterfly causes different color changes to its wings. They also created an interactive star atlas that shows different constellations and reveals their history with just a touch.