Collaboration between the University of Cincinnati, Sun Chemical, Polymer Vision and Gamma Dynamics has resulted in the development of a new display technology that provides visual brilliance equal to conventional printed media.
The electrofluidic display can potentially provide better than 85 per cent white-state reflectance, a performance level the researchers claim is a requirement before consumers will accept reflective displays in applications such as e-books, mobile phones and signage.
In the electrofluidic display, an aqueous pigment is placed inside a tiny reservoir. The reservoir comprises less than 10 per cent of the viewable pixel area and therefore the pigment is substantially hidden from view.
Voltage is then used to electromechanically pull the pigment out of the reservoir and spread it as a film directly behind a viewing substrate. As a result, the display takes on a colour and brightness similar to that of conventional pigments printed on paper.
When voltage is removed liquid surface tension causes the pigment dispersion to rapidly recoil into the reservoir.
‘If you compare this technology to what has been developed previously, there’s no comparison. We’re ahead by a wide margin in critical categories such as brightness, colour saturation and video speed,’ said developer Jason Heikenfeld, assistant professor of electrical engineering at the University of Cincinnati’s College of Engineering.
Because the optically active layer can be less than 15 microns thick, project partners at Polymer Vision see strong potential for rollable displays. The product offerings could be extremely diverse, including electronic windows and tunable colour casings on portable electronics.
Funding for the work was provided by Sun Chemical, Polymer Vision, the National Science Foundation (NSF) and the US Air Force Research Laboratory.
The pixel structure is able to reveal or hide the pigments with high contrast and video speed. The reservoir (centre circle) holds the pigment until it is ready to be displayed by application of voltage