How It Works
WARNING: This page is about a different car, the 2005 BMW 645Ci and 2004 BMW 645Ci. However, it is still accessible from the selected car via links, so may be relevant.
The wedge-shaped plastic film between the two glasses prevents the projected image from appearing double. The wedge-shaped plastic film aligns the images from the outer and inner glasses, preventing the display from appearing double.
Display with a conventional windscreen If a conventional windscreen is used, the projected image will be reflected onto both the inner and outer glass. This overlap will cause a double image.