Cincinnati, OH--Paper can be used as the substrate for electrowetting (EW) displays, as demonstrated by University of Cincinnati researchers Andrew Steckl and Duk Young Kim.1 The demo opens up the possibility of low-cost, flexible video-rate "e-paper" that could even be inexpensive enough for single-use throwaway applications.
The displays of e-readers such as the electrophoretic-based Kindle (and the liquid-crystal-based iPad, if you consider the iPad an e-reader) rely on complex circuitry fabricated on a rigid glass substrate. In EW, an electric field is applied to opaque droplets within a display to switch pixels on and off; conventional EW technology is also fabricated on relatively rigid substrates. But inexpensive paper as an EW substrate, combined with mass-production, could launch entirely new applications (lottery tickets with built-in video displays, anyone)?
The researchers found that the performance of their electrowetting device on paper is equivalent to that of glass, which is the gold standard in the field. The devices had low hysteresis (2%) and fast 20 ms switching times.
"It is pretty exciting," said Steckl. "With the right paper, the right process and the right device fabrication technique, you can get results that are as good as you would get on glass, and our results are good enough for a video-style e-reader."
Steckl imagines a future device that is rollable and feels like paper yet delivers books, news, and even high-resolution color video in bright-light conditions.
Steckl's goal is attract commercial interest in the technology for next-stage development, which he expects will take three to five years to get to market.
1. Duk Young Kim and Andrew J. Steckl, Applied Materials & Interfaces, Article ASAP, DOI: 10.1021/am100757g.
Posted by John Wallace
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