Alcatel has demoed a mobile phone with a transparent solar panel over the screen that would let users charge their phone by simply placing it in the sun.

The technology, unveiled at at CES in Las Vegas, sits over the screen and still allows users to use the phone completely unaware of the technology hiding in the display.

Although it's not likely to be commercially available until 2015, the company hopes that it will go some way to solving the daily issues of never having enough battery power.

Although it works, as shown to Pocket-lint in a private demo at CES, the company says that it doesn't believe it is good enough yet to release to the public.

"There are some issues with the viewing angles and the charging capabilities of the screen at the moment that we aren't happy with," Dan Dery, CMO, VP of Global Marketing and Products, told Pocket-lint.

Dery explained that the phone will work with direct sunlight as well as standard lights, in the same way regular solar panels.

In a quick demo of a device that most companies would be happy to launch commercially, we were able to get the prototype phone charging through a window in a Las Vegas hotel, knowing full well that the window would be tinted. Dery suggests that even if the light source wasn't enough to charge the phone it would more than likely be enough to hold the phone's idle power state so not using any of the battery.

While heavy users will no doubt relish the idea of simply leaving their phone on a window ledge to get a boost in battery life, the technology alsoopens up huge potential for developing countries in short supply of more traditional power suplies and would-be adventures heading away from the grid.

The technology should start to show up in phones from the company next year.