Disposable Dynamic Displays Use E-Ink on Real Paper

Mardi, 23 Novembre 2010 20:42

Disposable Dynamic Displays Use E-Ink on Real Paper

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Engineers at the University of Cincinnati have shown that under the right conditions, ordinary paper can be as dynamic as any screen.

“Nothing looks better than paper for reading,” says research leader Andrew Steckl. “We hope to have something that would

actually look like paper but behave like a computer monitor in terms of its ability to store information. We would have something that is very cheap, very fast, full-color and at the end of the day or the end of the week, you could pitch it into the trash.”

Steckl’s e-paper uses electrowetting — moving colored pigments from pixel to pixel with electronic charges — on a paper substrate. Electrowetting offers color, fast response times and video capability that current E Ink electrophoretic screens can’t match, but with similarly low power consumption.

Companies like Liquavista and Plastic Logic have prototype color e-readers that use this technology, but apply the electrowetting chemicals to a sheet of glass. The Cincinati team says its electrowetted paper offers the same performance as glass, but with greater flexibility and at a lower cost.

Steckl and grad student Duk Young Kim of U of C’s Nanoelectronics Laboratory presented their findings in the October issue of the American Chemical Society’s ACS Applied Materials and Interfaces journal. It was then reviewed in the November issue of Nature Photonics. The research was part of Kim’s doctoral dissertation.

“One of the main goals of e-paper is to replicate the look and feel of actual ink on paper,” write Steckl and Kim in the ACS article. “We have, therefore, investigated the use of paper as the perfect substrate for EW devices to accomplish e-paper on paper.”

“In general, this is an elegant method for reducing device complexity and cost, resulting in one-time-use devices that can be totally disposed after use,” the researchers note.

The ACS paper on electrowetting illustrates technical details of the process.

It’s still not easy, and industrializing the process will likely take some time. For maximum performance, the process involves a specific grade of paper with a particular surface coating, roughness, thickness and water uptake and a carefully controlled contact angle at which the electrowetted material is applied to the paper support. Electrowetted glass e-readers may appear sometime next year, but you’re unlikely to see disposable paper screens in newspapers or posters for at least three to five years.

Meanwhile, the Nanoelectronics team will continue experimenting with electrowetting on various flexible surfaces, with different fluids and electronic components, trying to maximize performance.

There’s a historical irony here. In the 19th century, “wet plate” photography involved applying a silver nitrate collodion solution to a glass plate. Eventually, George Eastman was able to take a dry collodion emulsion and apply it to ordinary paper, creating the first camera that ordinary people could use. After Eastman substituted celluloid film, which was stronger but just as flexible as paper, the rest was history.

UC Breakthrough May Lead to Disposable E-Readers [University of Cincinatti Press Release]

Image (top): Electrowetted E-Paper Display Mockup from Liquavista.

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