As a light source, OLED promises to be not only a lighter and thinner option, but also transparent. This means your car roof could be a window, letting in sunlight during the day, and at night, the same surface could turn into a light that comes on when the door is ajar. On a glass storefront, a lighted sign could display a sale, but would be transparent when turned off.

Offices could feature windows that bring in sunshine during the day and turn into lights in the evening, and other office lighting could be integrated into furniture or walls, rather than the ceiling. Car tail lights could also be replaced with OLED, allowing them to emit the same brightness with less bulk, so industrial designers of cars could make better use of the space or just provide consumers with a bigger trunk. At a recent conference, the Philips team used OLED-lighted nametags powered by batteries.

via The Future of Screens: Why OLED Will Change Everything.