Japan’s second biggest mobile phone carrier KDDI au today unveiled the first model of its summer line-up for the Japanese market (have a look at their spring models here). In cooperation with Sharp, KDDI au will offer a cell phone that will be waterproof and, more interestingly, powered by solar energy [JP].

The yet unnamed device has a tiny solar panel behind the lid, making it possible to charge the phone through the power of the mighty sun. KDDI au claims 10 minutes of a solar charge is enough to be able to make a quick phone call (one minute) or use the phone on standby for an impressive 120 minutes.

Needless to say, the phone will also come with a conventional battery that can be charged up to 80% via solar power.

The phone will be sold in Japan from June. Plans for other markets are not yet on the table.