Delighted with power savings
23 August 2011
Technology created by UCLA engineers allows LCDs to recycle energy.
It’s always on your mind. Will the charge on the smartphone or laptop run down? Will there be access to a plug socket?
But those days are now gone because new technology developed by researchers at the UCLA Henry Samueli School of Engineering and Applied Science could help to solve the problem.
UCLA engineers have created a concept for harvesting and recycling energy for electronic devices that involves equipping LCD screens with built-in photovoltaic polarises, allowing them to convert ambient light, sunlight and their own backlight into electricity.
LCDs work by using two polarised sheets that let only a certain amount of a device's backlight pass through. Tiny liquid crystal molecules are sandwiched between the two polarisers, and these crystals can be switched by tiny transistors to act as light valves. Manipulating each light valve, or pixel lets a certain amount of the backlight escape; millions of pixels are combined to create images on LCDs.
The UCLA Engineering team created a new type of energy-harvesting polariser for LCDs called a polarising organic photovoltaic, which can potentially boost the function of an LCD by working simultaneously as a polariser, a photovoltaic device and an ambient light or sunlight photovoltaic panel.
"I believe this is a game-changer invention to improve the efficiency of LCD displays," said Yang Yang, a professor of materials science at UCLA Engineering and principal investigator on the research. "In addition, these polarisers can be used as regular solar cells to harvest indoor or outdoor light. So next time you are on the beach, you could charge your iPhone via sunlight."
The researchers say that from the point of view of energy use, current LCD polarisers are inefficient. A device's backlight can consume 80% to 90% of its power, but as much as 75% of the light generated is lost through the polarisers. A polarising organic photovoltaic LCD could recover much of that unused energy.
"In the near future, we would like to increase the efficiency of the polarising organic photovoltaics, and eventually we hope to work with electronic manufacturers to integrate our technology into real products," said Yang. "We hope this energy-saving LCD will become a mainstream technology in displays."
Rui Zhu, a postdoctoral researcher at UCLA Engineering and the paper's lead author, added: "Our coating method is simple, and it can be applied in the future in large-area manufacturing processes."
Youssry Botros, Program Director for the Intel Labs Academic Research Office, which supported the research, commented: "The polarising organic photovoltaic cell demonstrated by Professor Yang's research group can potentially harvest 75% of the wasted photons from LCD backlight and turn them back into electricity. The strong collaboration between this group at UCLA Engineering and other top groups has led to higher cell efficiencies, increasing the potential for harvesting energy. This approach is interesting in its own right and at the same time synergetic with several other projects we are funding through the Intel Labs Academic Research Office."
Ankit Kumar, a materials science and engineering graduate student at UCLA Engineering was the paper's second author.
Yang, who holds UCLA's Carol and Lawrence E. Tannas Jr. Endowed Chair in Engineering, is also faculty director of the Nano Renewable Energy Center at the California NanoSystems Institute at UCLA.
The research was supported by Intel through a gift to UCLA, and by the Office of Naval Research.
Contact Details and Archive...
Related Articles...
Most Viewed Articles...