UCLA Engineers Create Energy-Generating LCD Screen 108
An anonymous reader writes "Engineers at UCLA have developed technology that allows gadgets like smartphones and laptops to convert sunlight, ambient light, and their own backlight into energy. Equipping LCD-enhanced devices with so-called polarizing organic photovoltaics will recoup battery loads of lost power, and enable smartphone users to scour Yelp, scan Twitter, and update their Facebook page without fear of draining the charge before a real communication crisis arises."
Re:Huh? (Score:4, Interesting)
LCDs work by creating a whole bunch of light, and then filtering out the light that isn't needed. That's why black isn't truly black on LCD screens -- the backlight is still on, the screen is just filtering out as much light as it can. If they have a way to recapture that light, which otherwise goes to waste, then it will provide substantial energy savings, especially considering that the screen often consumes as much energy as the rest of the phone combined.
Re:Huh? (Score:5, Interesting)
LCD forms images when the crystals align in a particular way to block the backlight. Now in addition to forming an image, those crystals blocking photos are tapped to recoup a charge.
Idea for a better source of energy (Score:3, Interesting)
Re:Huh? (Score:5, Interesting)
The only way converting backlight to energy works is by stealing photons (effectively dimming the display), and putting it through a level of inefficiency.
You're assuming they're stealing it from the final output. What they've actually done is replace the standard polarizing filter that LCDs use with their own filter that captures the filtered photons. Those photons are already being lost by design [wikipedia.org], so capturing them is entirely beneficial. For a quick car analogy, think of it as a flywheel for your LCD. You're going to be doing something that consumes energy anyway, and most of that energy would be wasted otherwise, so you might as well make a point of capturing some of it for your use. Plus, the article indicates that as much as 75% of the energy is lost to polarization, so there's plenty of light to grab there.