Transparent OLEDs might not make a lot of sense in televisions, but what about putting them in your car? Philips and chemical company BASF have developed a prototype car roof that combines OLED panels with transparent solar cells. During the day, the roof lets in light from outside, which also charges the solar cells. At night, the panels turns into a car light, using the power stored earlier.

In theory, this isn't all that different from the transparent OLED or smart window concepts we've written up before, including ones specifically designed for cars. However, the implementation for this is simple and (relatively) practical, using the OLED for light rather than as a screen or augmented reality display. It's also the first design we've seen with solar panels layered directly onto a transparent OLED. If it's anything like the concept above, you won't be getting a single, solid window (possibly for strength or security reasons), but the ceiling window isn't exactly there for looking at scenery anyways.