|Matthew Hagedon of UC holds a sample of electrofluidic imaging film. The white plastic film, ten times thinner than a sheet of paper, is in a rigid frame for support during lamination into a display. The goal is to create a large roll of film that can be laminated onto electronics. (Image: UC)
Cincinnati, OH--A screen of paper-thin plastic, termed "electrofluidic imaging film,” developed by researchers at the University of Cincinnati's Novel Devices Laboratory, has switchable colored pixels that have no space-taking border geometry. The UC group partnered with start-up company Gamma Dynamics in the research.
“This is the first of any type of electrowetting display that can be made as a simple film that you laminate onto a sheet of controlling electronics," says Matthew Hagedon, one of the UC researchers. "Manufacturers prefer this approach compared to having to build up the pixels themselves within their devices, layer by layer, material by material. Our proof-of-concept breakthrough takes us one step closer to brighter, color-video e-paper and the Holy Grail of rollable/foldable displays.”
The white, porous film is coated with a thin layer of reflective electrodes and spacers that use sophisticated fluid mechanics to electrically transport colored ink and clear-oil fluids that define the pixel areas. The research is published this week in the journal Nature Communications.
In current electrowetting displays (devices that use electricity to move pigmented fluids around), colors maintain their image-forming distinctiveness via pixel borders that ensure that the pixel's color does not bleed over into the next pixel or color. This matters because pixel borders are dead areas that dull any display of information, whether a display of text or image. Leading electronics companies have been seeking ways to reduce or eliminate pixel borders to increase display brightness.
“For example, the pixel border in current electrowetting displays, which prevents ink merging, takes up a sizable portion of the pixel," says Jason Heikenfeld, another UC researcher. "This is now resolved with our electrofluidic film breakthrough. Furthermore, our breakthrough provides extraordinary capability to hide the ink when you don't want to see it, which further cranks up the available brightness and color of the display when you do want to see it. With a single, new technology, we have simplified manufacturability and improved screen brightness."
The electrofluidic imaging film is part of an overall UC design that will require only low-power to produce high-speed content because it makes use of ambient light instead of a light source within the device. First-generation foldable e-devices will be monochrome; color will come later. Eventually, within 10 to 20 years, e-devices with magazine-quality color, viewable in bright sunlight but requiring low power, will come to market. Such a device will require low power to operate since it will charge via sunlight and ambient room light. However, it will be tough and only use wireless connection ports, such that it could be dropped, washed clean, or left out overnight in the rain. (See http://www.uc.edu/news/nr.aspx?id=13030)