American researchers have brought us one step closer to realising foldable, rollable e-devices

The Kindle and other e-reading devices may have done one over on the traditional book, but they fall down in their chunkiness, slowness and limited facilities.

Researchers from the University of Cincinnati, in conjunction with spin-out Gamma Dynamics, have just shown how the use of electrofluidic imaging film may lead to foldable, nay rollable, e-devices that could show text, images and video.

Electrofluidic imaging film is a white, permeable material coated with a layer of reflective electrodes and spacers. Through electric fluid mechanics manipulation, ink and clear fluids can be transported through the film to create words or pictures on screen.

A major obstacle to creating rollable devices has been the screen, currently made of glass. E-paper researchers have put countless man-hours into trying to manufacture a paper-thin plastic that could roll like fabric and serve as a screen. Electrofluidic imaging film may solve this problem.

The plastic film has a porous membrane and it is within this membrane that coloured ink and clear oils are transported through the fluid mechanics to fill the screen in every corner. The designers claim it is strong enough to be rolled up thousands of times and still function.

“The research is impressive and these guys are ahead of many others working on e-paper technology,” says Prof Gerald Farrell, director of the photonics research centre and head of the school of electronic and communications engineering at DIT.

“Their work is just a proof of principle. They’re not showing off something that’s actually akin to a magazine page. But the technology has the potential to be used for rollable displays.”

Challenges

Several techniques have been used to improve e-paper technology – electrokinetics, polymer vision, electrochromism, etc – but challenges persist in realising the coveted fully functional and rollable e-device.

The first is power. “Traditional LCD displays require an emission of light to be viewed,” says Farrell. “To see a picture on a screen, there has to be a source of light. A magazine needs no energy as it only requires reflective light to be seen.

“E-device screens have to generate their own light and therefore they use energy. The bigger the display, the more energy they use. The bulk of battery usage on an iPad or smartphone isn’t running apps. It’s keeping the display going.”

The University of Cincinnati design overcomes this by making use of ambient light rather than a high-powered internal light source, meaning it requires only low power demands but is able to produce high-quality content and functionality.

Another specification this new technology has in its favour is speed, the lack of which has dogged similar technologies. “It has a very fast response time so it could be used for video,” says Farrell.

“Conventional e-books don’t have the capacity for video. If you tried to run a movie on a Kindle it would just look like a smudge on the screen. The display can’t change fast enough. You can’t even turn the pages that quickly on a Kindle.”

Given how much research and interest there is in e-paper technology, it is only a matter of time before we see some impressive stuff on the market. But Farrell believes there are hurdles to overcome before rollable devices are widely available.

“It still requires a lot of power to put video on paper so that will need to be addressed. Then you would have to question the robustness of any device that must be durable enough to roll up hundreds, even thousands, of times. Another issue is how reliable the porous membrane of the electrofluidic technology is.

“If there was major investment into the research, I could envisage it being ready in five years. But at the moment it’s just a spin-out from a university.”

Financial resources

Farrell adds: “Put it another way: Samsung totally dominates the LCD TV market, and everyone can have cheap LCD TVs because of the massive investment that was put in. Gamma doesn’t have those financial resources.”

In some cases too much competition can be a bad thing. “There are loads of competing technologies out there,” says Farrell. “Sometimes new technology gets to market faster when there are just a small number of groups working in a niche area like this.

“But giants like Hewlett-Packard and Canon see the writing on the wall for a lot of their printing products and paper-based technologies. They have been trying to create new types of e-paper technology also and know it will ensure their place in future markets.

“The fact is we have been completely reliant on paper for centuries. So whatever replaces it will have to be very robust indeed.”