New electronic ink display brings e-paper revolution a step closer

20:43 May 12, 2009 PDT

The Sun Chemical pigment dispersions that provide e-paper with the same brilliant colorations as printed paper

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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.

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