Samsung Mobile Display show a 2 inch transparent OLED display at the FPD International 2009.

At the FPD-International, a mirror is placed behind the display to show that the back side of the display also shows an image.

As we reported Samsung shows some Transparent OLED, here are the technical details for you:

Samsung inspire us with transparent OLED TV prototype at CES-2009!

The Oled-A association has shown off a transparent Oled at Ces-2009 produced from Samsung!

The technology, which is actually called TOLED, offers a screen that is 70-85% transparent when switched off, nearly as clear as the glass or plastic on which it's built on.
The end result is that you can see objects on the other side when the television is on.

For many the ideal form of in car electronics like GPS navigation systems and entertainment devices like TVs would be clear devices that only show up when in use.