Why is a monitor with a refresh rate of at least 100 Hz, or better 120 Hz, required?

At the selected resolution, the monitor must reach a refresh rate of at least 100 Hz (120 Hz is better), as the 3D glasses cut the actual refresh rate in half and a 3D effect isn't visible at rates of less than 50 Hz. Flat (LCD) screens are not suitable for the display of stereo modes since they generally can only display a maximum refresh rate of 75 Hz.

Shutter glasses work by covering the eyes alternately. At a setting of 120 Hz, the shutters close 120 times per second, 60 times for each eye.
A very simple test shows how the ELSA 3D REVELATOR works: Target a distant object over your thumb. First, close your right eye and make a note of the position of the object. Next, close your left eye and open the right. The object being viewed now appears slightly shifted to one side. This technique, applied to each eye 60 times per second, produces the spatial effect used by the ELSA 3D REVELATOR. At settings of less than 120 Hz, the picture will start to flicker.