New Filter Could Make LCDs >400% More Efficient

lcd screen pixels photo

Photo: Flickr, CC
Negawatts Strike Back
The immensely popular LCDs screens that are found everywhere in the modern home (television, computer, laptop, cellphones, etc) use less energy than CRTs, the previous technology, but they are still far from being optimally efficient. Only about 8% of the light emitted by a LCD's backlight makes its way out, and the rest is wasted. But that might be about to change thanks to a new filter that could boost that efficiency by more than 400% and allow around 36% of the light to pass through. Read on for more details.
LCD schematics image

Image: Wikipedia, CC
Normally, LCDs use several layers of optical devices to colorize, polarize, and shutter light from a backlight, and inefficiencies emerge at every step. Now researchers at the University of Michigan have made an optical film that promises to boost the overall efficiency of LCDs [...]

The color filter is a three-layer sandwich of an insulating material in between two layers of aluminum; the entire stack is less than 200 nanometers thick and is etched with periodic slits, like a grate. The distance between the slits and their width determines the color they'll produce when illuminated by a white backlight. This is because the grating patterns are on the same size scale as the wavelength of visible light.

Better And Cheaper
The beauty is that this new filter is actually simpler to make than the current ones, from a manufacturing point of view, meaning that if it goes in production, it could eventually mean that LCDs would be both more energy-efficient (significantly so) and cheaper.

For televisions, such a technology would make a big difference because most people have their TVs on during peak electricity demand periods, when conserving energy provides the biggest benefits. It would also make a big difference to office buildings that have thousands of computers with LCDs screens, and it would increase the battery life of portable electronics significantly since the screen is one of the biggest battery drains.

The researchers are currently working on making this technology production-ready, and they claim to have methods of printing such filters with a roll-to-roll approach.

Via Technology Review
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