Some companies are busy stuffing big batteries in smartphones and tablets, to help them run longer. Others are making it easy to quickly charge the battery so you don’t have to spend much time plugged in.
Japanese electronics company Kyocera has another idea: solar-powered phones.

At Mobile World Congress this week, Kyocera is showing off a new smartphone prototype with a solar panel built into the screen.
That means you don’t need to flip the phone over to expose its backside to the sun’s rays to charge the batteries. It can charge while you’re using it, face up.
The Kyocera smartphone prototype has a 5 inch full HD screen, a waterproof design, and Android software. But since Kyocera hasn’t announced any plans to actually ship a phone with this technology, it’s always possible those specs could change before we see this type of solar-powered phone hit the market.
Kyocera worked with Sunpartner Technologies on the prototype, and the companies say that 3 minutes of light exposure could provide 1 minute of talk time. Clearly it would take a while to fully charge a smartphone battery this way, but in emergency situations where there’s no way to plug in, the solar panel could let you get enough power to call for help… or play a little Candy Crush in the woods.
The company also figures the phones could be used by outdoor workers, allowing them to charge their phones in the field.
Sunpartner, by the way, is also showing off a solar-powered cover for an eReader designed with Bookeen.