3D TVs use a specially designed screen that can display two different versions of a video image by alternating the video frames at very high speed. 3D video is basically two full-resolution 1080p images, one for your left eye and one for your right. The shutter glasses' lenses darken and lighten rapidly in coordination with the screen's flashing images. The timing of the shutter glasses is wirelessly controlled by an "emitter" that is usually built into the TV. The system creates an immersive viewing experience.