Car Windows and Polarized Sunglasses

Polarized sunglasses work by selectively blocking out light that is polarized in a particular direction. Direct sunlight is not strongly polarized in any particular direction. But, in general the reason polarized sunglasses are better than regular shades is that light reflected from road surfaces or water tends to be polarized. By using polarized material, a lot of the glare sources (such as road reflections or water reflections) are cut out. Regular shades can not cut out the glare source, they can only dim them. What is happening with the window tinting is that the material used to tint the glass polarizes the incoming light. So the pattern you see with the polarized sunglasses on is related to the light being polarized as it passes throught the tinting material. Most 3-D films now use polarization to create the 3-D effect. Roughly speaking, By projecting images through a polarizer initially and then having the glasses on, the polarizers in one side of the glasses blocks one image and transmits another, and vice versa on the other side. The eyes then get two different images which creates the 3-D effect.