Team develops super-hi-def displays

Posted by Emma Woollacott

A new, ultra-high definition color display technology has been developed, allowing a University of Michigan team to create an image of their logo measuring just nine microns high.

The pixels in the displays are about an order of magnitude smaller than those on a typical computer screen, and about eight times smaller than the pixels on the iPhone 4.

Jay Guo, an associate professor in UM's Department of Electrical Engineering and Computer Science, has developed a new type of color filter made of nano-thin sheets of metal with precisely spaced gratings.

The gratings, sliced into metal-dielectric-metal stacks, act as resonators, and trap and transmit light of a particular color.

"Amazingly, we found that even a few slits can already produce well-defined color, which shows its potential for extremely high-resolution display and spectral imaging," Guo said.

Red light emanates from slits set around 360 nanometers apart; green from those about 270 nanometers apart and blue from those 25 nanometers apart. The differently spaced gratings essentially catch different wavelengths of light and resonantly transmit through the stacks.

He says the technology could be useful in projection displays, as well as bendable or extremely compact displays. The military apparently sees applications, as the research is partly funded by the Air Force Office of Scientific Research and DARPA.

With a conventional LCD, only about five percent of the back-light reaches our eyes, Guo said. They contain two layers of polarizers, a color filter sheet, and two layers of electrode-laced glass in addition to the liquid crystal layer.

Guo's color filter acts as a polarizer simultaneously, eliminating the need for additional polarizer layers. And because these new displays contain fewer layers, they would be simpler to manufacture, he said.

The university's applied for a patent and is looking for commercial  partners.