Electronic Paper One Step Closer

UBC Reports | Vol.
51 | No. 7 |
Jul. 7, 2005

Display companies testing prototypes that use new technology

By Brian Lin

Anyone who’s ever had trouble reading their cell phone or PDA display will appreciate a new technology being developed at UBC’s Structured Surface Physics Laboratory (SSP) that promises to deliver electronic displays as clear as ink on paper.

Based on an invention of UBC Vice President Academic and Provost Lorne Whitehead — who is also chair of SSP — the “electronic paper” has received 15 U.S. and international patents and provided the foundation of a spin-off company — aptly named CLEAR Display Inc.

Conventional liquid crystal displays (LCDs), which use fluorescent backlighting and layers of liquid crystals against a glass-like surface to create images, show up poorly in strong, external light sources.

“This is why in the sun, it’s really hard to read your PDA or cell phone,” says Michele Mossman, a research associate in the Department of Physics and Astronomy, and the primary UBC researcher developing the technology.

Several years ago, Mossman and Whitehead invented an approach that takes advantage of a well-known physics phenomenon called Total Internal Reflection (TIR) that enables the display to create crisp, high-contrast and high-resolution images comparable to ink on paper.

By adding microscopic optical hemispheres on the back of a thin, plastic film, they have created a surface that is receptive to coloured pigment particles, which absorb rather than reflect light.

“We can use an electric field to cause the pigments to gather in desired regions to form images. In a way, it is a bit like the children’s toy called the Etch-a-Sketch,” says Mossman. “By selectively removing particles from a surface, an image can be created. But in our case, this happens in just milliseconds and yields strong contrast.

“Since TIR is essentially 100 per cent efficient and the hemispheres reflect ambient light, very little power is required and the quality of the display is good under a wide range of lighting conditions.”

“We’re now working with a few display companies in prototype development and to explore the potential of incorporating the
technology into existing displays,” says Mossman, who adds that the paper-like quality of the display will enable tools such as electronic books to become much more user-friendly.

A Massachusetts Institute of Technology spin-off company called E-ink is working on one of the competing technologies on the
market. While commercial products are already being sold based on the MIT technology, it only achieves about half the maximum reflectance of CLEAR displays, which under common lighting conditions exceeds that of white paper.

“One of the most exciting aspects of this technology is its positive environmental potential,” says Whitehead. “In today’s world of electronic information it is a shame that so much paper is wasted in order to display information in an easy-to-read, portable form. We hope this work will bring ‘electronic paper’ one step closer to reality.”