Visualizing the Viewing Planes of a "Glasses-Free" Autostereoscopic 3D Monitor.

One of the questions I'm often asked is "why aren't these monitors in movie theaters yet?" The answer to this question is that, although crowds of people can simultaneously view the same monitor and see the 3D effect, there are some spots where the image becomes blurry.

Imagine that there are 9 lines coming out of the 3D display, all from a point in the center of the display, spreading out horizontally. These 9 lines are the viewing planes. When your head is within a range close to the viewing planes, you are in the "sweet spot" and can see the 3D effect perfectly in focus. However, if you move your head horizontally, when it is near the middle of two adjacent viewing planes, the 3D image becomes a little blurry, until you're head once again is close to a viewing plane.

In the image below, the viewing planes are the red lines. If your eyes are both within the range of the blue lines that surround the red lines (viewing planes) you can see the 3D effect. If your eyes are not both within the blue lines, the image becomes slightly blurry.