Over 90 percent of the displays sold will use liquid-crystal display (LCD) technology. However, LCDs are tremendously energy inefficient, converting only about 5 percent of the light produced by a backlight into a viewable image. The LCD in a notebook computer consumes one-third of its power. MIT’s Technology Review reported on efforts at the University of Michigan to improve the efficiency of LCD panels and boost the battery life of phones and laptops.
The LCD screen remains dominant because manufacturers can make LCDs inexpensively on a vast scale. More energy-efficient displays are either too expensive to manufacture or cannot produce high-quality images. “The LCD is very inefficient, but it works,” Jennifer Colegrove at Display Search, a market research and consulting firm, told TR.
At Michigan, they are tackling one of the biggest culprits of wasted light in LCDs: color filters. The group, led by Jay Guo, is developing energy-harvesting color filters. Color filters are used in many displays, but the ones by Professor Guo’s team are appropriate for use in reflective “electronic paper” screens. These contain sub-pixel arrays that absorb ambient light and reflect red, green, or blue light.
Energy efficiency at Michigan
Dr. Guo and his U of M colleagues combined a common polymer solar cell material with a color filter that his group invented last year. The photovoltaic color filter converts about two percent of the light that would otherwise be wasted into electricity.
U of M’s Guo estimates that full displays incorporating this photovoltaic filter could generate tens of milliwatts of power, enough to extend the life of a cell phone battery. The photovoltaic color filter is described in a paper published online in the journal ACS Nano.
“It’s an intriguing idea,” says Gary Gibson, a scientist developing reflective color displays at HP Labs in Palo Alto, California. Low brightness is a recurring problem for color electronic paper. If the color filter proves practical, says Gibson, energy harvested from ambient light could power a backlight and make the display brighter.
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Harvesting energy from the environment with the device is a trick that could boost the battery life of phones and laptops. Oh yeah, the article also talked about similar work at UCLA. Go Blue!
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- French startup develops solar-charging displays (thedroidguy.com)
Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.
