Global Sources
EE Times-Asia
Stay in touch with EE Times Asia
EE Times-Asia > Optoelectronics/Displays

LCD filter turns light into energy

Posted: 21 Oct 2011 ?? ?Print Version ?Bookmark and Share

Keywords:color filter? solar cell? energy efficiency?

Researchers at the University of Michigan's (UMich) Department of Electrical Engineering and Computer Science have developed a reflective PV color filter that can also function as a solar cell. The device touts energy-harvesting features that can potentially improve energy efficiency of mobile electronic devices such as e-readers and mobile phones.

In traditional LCDs, less than eight percent of the backlight actually reaches a viewer's eyes. The rest is absorbed by color filters and polarizers, stated Jay Guo, a professor at UMich. "This absorbed light is totally wasted. It becomes heat. You can feel it if you put your hand close to a monitor. Why not try to harvest some of this energy?"

photovoltaic color filter

Photovoltaic filters of different colors. (Source: The University of Michigan)

That's just what he has done. Guo's new filter can convert to power about two percent of the light that would otherwise be wasted. This could add up to a significant amount in small electronics, he noted. The researchers created the filter by adding organic semiconductor solar cells to an elegant and ultra-thin color filter, similar to what Guo's lab had created more than a year ago. That filter is composed of nano-thin sheets of metal with precisely spaced gratings that act as resonators, trapping and reflecting light of a particular color. The color depends only on the amount of space between the slits.

At just 200nm thick, the filter is 100 times thinner than traditional colorant-based filtersa feature that would be attractive in future ultrathin colored display devices. The technology could also potentially be used in larger displays to make energy harvesting billboards or decorative solar panels.

- Julien Happich
??EE Times

Article Comments - LCD filter turns light into energy
*? You can enter [0] more charecters.
*Verify code:


Visit Asia Webinars to learn about the latest in technology and get practical design tips.

Back to Top