ElectroWetting

Based on a technology called electrowetting, Philips’ new display concept is already attracting considerable attention. From a scientific perspective it’s a fascinating breakthrough, already featured in a recent volume of the prestigious international journal, Nature. For consumers, it holds out the prospect of displays that are easy on the eye and a pleasure to use. And while books with ‘moving pictures’ may be well into the future, closer to today video-speed electronic-paper is likely to enable energy-efficient mobile displays that don’t become almost invisible as soon as you step into a brightly lit area.

How does it work?

How can video-speed electronic-paper be such a delight for the eyes? In short, because it enables the visual properties that people like about paper, something existing display technologies simply can’t do.

First and foremost, it’s a ‘reflective’ technology, which means just like paper it reflects ambient light. So unlike other types of display, if you’re in a well-lit space or outside, you can still see the display easily – from any angle and with the same high contrast. And it doesn’t need backlighting, in contrast to the LCDs currently used in mobile devices.

In fact, the technology can be used to build a low-power, low-voltage reflective full-color display that’s at least twice as bright as is possible with any other technology. Furthermore, because displays based on electrowetting technology don’t need polarizers, they have the potential to be four times as bright as reflective LCDs. As mobile multimedia and smart handhelds become ever-more popular, a display technology that makes watching outdoors more enjoyable clearly has strong market potential.

Philips has been able to develop this extremely exciting display technology due to its leadership in the field of electrowetting devices. Surprisingly, as Rob Hayes explains, the basic electrowetting principle is over one hundred years old, however it’s only recently become possible to translate it into real devices.

“The idea of electrowetting was understood as early as the late nineteenth century, but it’s only with the development of modern materials that we’ve been able to put it into practice. At Philips we’ve been exploring the possibilities of this technology for about ten years and have built up considerable expertise in this field. Many other research institutions draw on our know-how in materials and fabrication techniques.”

In brief, Philips’ unique electrowetting-based video-paper is a microfluidic technology that involves controlling the shape of a confined water / oil interface with an applied voltage. (The confined water/oil ‘droplets’ form the display pixels.) When no voltage is applied, the water and oil form a stack and a colored pixel is visible. Applying a voltage causes the interface between the colored oil and water to move aside like a curtain. This creates a partially transparent pixel, or if a reflective white surface is used under the switchable element, a white pixel. http://www.newscenter.philips.com/InformationCenter/NewsCenter/FArticleDetail.asp?lArticleId=3023&lNodeId=13