Touch Screen displays are usually associated with layer upon layer of electronic and chemical components. However, researchers have managed to turn regular old paper into a touch screen display using a sensor and color-changing inks. It could mean the beginning of interactive books, paintings, museum displays or even wallpaper.
Kohei Tsuji and Akira Wakita of Keio University in Japan are behind the new touch screen display, which has color-changing inks printed on one side, and conducting pastes painted on the other side to create an electric circuit. The effect is an interactive display that maintains the flexibility of regular paper.
New Scientist writes, "It's like finger painting, only without the messy paints." And when you watch the video, that's fairly accurate -- though you aren't necessarily in control of how the paints wash across the page. With this new technology, a touch turns on the display and the paper starts shifting color.
"Touching the paper activates a copper pressure sensor taped on the back of the paper. This sends electricity through the painted silver wires, which warms electrodes made from carbon paste. Heat radiates through the paper to the colour-changing ink on top. This ink is a liquid crystal and the molecules within it organise into twisted helices when warmed. The natural structure of the helices interacts with light and reflects only some wavelengths. The material changes colour from red to blue to green as it warms because the liquid crystal structure changes with temperature."
Here is a video showing how the display performs -- touching one part of the paper can start up changes all over.
The new display could potentially be used in books, allowing for interactive stories that don't have the same level of electronic components or energy consumption as tablets or e-readers. Though it could even become a medium for artists.
Discovery News reports, "The idea is to bring interactivity to ordinary paper. Touch screens are complicated to make, and are of course rigid. But for artists who want to use the unique qualities of paper and take advantage of the tactile nature of paint, this technique offers a beautiful and simple solution. It also allows for a kind of animation -- done by showing and hiding different colors."
I'm curious about details such as how long these displays last as ink and paste age, how this affects the recyclability of the paper, and if there are substances within the inks or paste to be concerned about. If these issues are worked out, this could be a really amazing way to make posters and books engaging without using more energy- and materials- intensive tools like tablet devices.