By Stephen Schenck | August 12, 2011 2:24 AM
Check out what apps, hardware, and services are putting the biggest dent in your smartphone’s battery life, and you’ll likely find the display right up there at the top. AMOLED screens generate their own light, but for LCD-based systems, whether a pixel is black or white, the backlight behind it is still running full-blast, wasting a good deal of its output. A group out of UCLA has a new idea for how to make lemonade out of those lemons, adding photovoltaic elements to the LCD to harvest some of that wasted light and turn it back into electricity to help keep your smartphone charged.
Until there’s a working prototype built-in to a modern smartphone and given some real-world testing, it’s difficult to say just what effect this system could have on battery life, but the team claims that up to 75% of generated light is blocked by the LCD before it can exit the phone, and of that fraction, maybe 75% of it could be harvested with by photovoltaic elements that means turning a little over half of all light produced back into electricity. Of course, photovoltaic cells aren’t 100% efficient, so we’d see only a fraction of that fraction of that fraction of light returned to your phone as electricity, but every little bit helps.
In addition to reclaiming that lost light, making the LCD photovoltaic would also allow it to turn incoming light, whether from the sun or overhead lamps, into power; we haven’t heard any estimates on what effect those might have on extending battery life. We’ve heard of similar ideas before, but using a photovoltaic panel that sits on top of the LCD, missing out on all the wasted light underneath. All in all, it sounds like a great idea, assuming the photovoltaic elements can be added to LCDs without decreasing transparency (notice the tint in the image above), and that the technology doesn’t raise a phone’s cost too much.