May 13, 2009 A new electronic ink display technology has been developed at the University of Cincinnati. This new technology, called an electrofluidic display (EFD), creates a reflective display that can produce color and contrast ratio of up to 85 percent what normal paper can achieve, promising a new generation of full-color electronic readers.

In the past, electrowetting for electronic reading displays, considered one of the more promising technologies, has been limited because is it only creates a black and white display and the contrast between the blacks and whites is less than ideal, at best achieving an appearance that has been described as a "dirty newspaper". Also the refresh rate of displays using this technology is relatively slow, not allowing for smooth video display, which limits its potential applications.


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The new electrofluidic display, though, stores color pigments in a small portion of the pixel, and uses an electric charge to draw them out over the whole pixel in much the same manner as electrowetting. As a result, the display takes on a bright color that is similar to the pigments of natural paper.

Professor Jason Heikenfeld, from the Unversity of Cincinnati says: "The ultimate reflective display would simply place the best colorants used by the printing industry directly beneath the front viewing substrate of a display. In our EFD pixels, we are able to hide or reveal colored pigment in a manner that is optically superior to the techniques used in electrowetting, electrophoretic and electrochromic displays."

Importantly, the electrofluidic display – developed by an international collaboration of the University of Cincinnati, Sun Chemical, Polymer Vision and Gamma Dynamics – can be less than 15 microns thick, which opens the door to the technology being used in displays that can easily bend or be rolled up into a cylinder.

A new company, Y–Dynamics, has been set up to exploit the commercial possibilities of the technology.

Stephen Saunders

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