MacRumors have just reported on a patent filed by Apple that shows how they see a possibility to integrate solar cells into the display panel.
Solar panels will have to get much more efficient and power-drain reduced down to the sub 5W range before this technique has legs for any form of general computing device. Screens are never used in direct sunlight and I'm sure that the LCD layer will reduce efficiency by a huge amount but considering that its one of the largest available areas on any portable device, it makes sense to start thinking about it for the future.
