University of Michigan scientists have created pixels that will enable LED-projected and -wearable displays to be more energy efficient with more light manipulation possible - all on a display that may eventually be as small as a postage stamp.
The research was funded by the Air Force Office of Scientific Research (AFOSR). The technology was developed by Dr. Jay Guo, associate professor in the Department of Electrical Engineering and Computer Science; graduate student researchers Ting Xu and Yi-Kuei Wu; and collaborator Dr. Xiangang Luo.
The nanostructuring technology includes a new color filter made of nano-thin sheets of metal-dielectric-metal stack, which have perfectly-shaped slits that act as resonators. They trap and transmit light and transform the pixels into effective color filtering elements.
The pixels created from this technology are ten times smaller than what are now on a computer monitor and eight times smaller than ones on a smart phone. They use existing light more effectively and make it unnecessary to use polarizing layers for liquid crystal displays (LCDs). Prior to this technology, LCDs had two polarizing layers, a color filter sheet, two layers of electrode-laced glass and a liquid crystal layer, but only about five percent of the backlighting reached the viewer.
The research exploits nanophotonic devices using plasmonic structures.
"Most of the applications of the new technology suffer from the absorption loss by the presence of metal structure that is an integral part of the plasmonic devices," said Guo.
However, the loss in structure can be managed to produce useful devices that are valuable to the Air Force, which is considering the technology to be used as part of virtual displays integrated to pilots' windshields.
In the future, the scientists are expecting to use nanoimprint lithography to begin making the next generation of color filters.
"We hope to show that the fabrication of these structures can be scaled up to large areas and can be very cost effective," said Guo.