Varible focus stereoscopic display system and method

1. A variable focus stereoscopic display system modifying a focus distance for viewing a stereoscopic display receiving image data, the variable focus stereoscopic display system comprising:

a first lens positioned between a first eye and the stereoscopic display;

a second lens positioned between a second eye and the stereoscopic display; and

wherein the first and second lenses are configured to modify the optical power for the variable focus stereoscopic display system and therefore the focus distance, the modification of the focus distance consisting of being based solely on a vergence of the first and second eyes, and changes in the focus distance are positively correlated with changes in a convergence distance of lines of sight of the first and second eyes.

2. The variable focus stereoscopic display system of claim 1 wherein the first and second lenses are calibrated to provide about a zero optical power at a viewer preferred focus distance.

3. A variable focus stereoscopic display system for viewing a stereoscopic display which receives image data, comprising:

a focus plane having an associated focus distance;

a first lens positioned over a first eye for viewing the stereoscopic display; and

a second lens positioned over a second eye for viewing the stereoscopic display, the first and second lenses each configured to provide a first optical power or a second optical power to increase the focus distance as a convergence of the first eye and the second eye decreases, and to decrease the focus distance as the convergence increases, the increase or decrease in focus distance being performed independently from the image data.

4. The variable focus stereoscopic display system of claim 3 further comprising:

a sensor configured to sense an amount of the convergence; and

a controller configured to modify the optical power of the first and second lenses in response to the amount of the convergence.

5. The variable focus stereoscopic display system of claim 3 wherein each of the first and second lenses comprise:

a first portion having a first optical power; and

a second portion having a second optical power greater than the first optical power.

6. The variable focus stereoscopic display system of claim 3 further comprising:

a sensor configured to sense an amount of the convergence;

a controller configured to modify the optical power of the first and second lenses in response to the amount of the convergence;

a third lens positioned between the first eye and the stereoscopic display; and

a fourth lens positioned between the second eye and the stereoscopic display; wherein each of the third and fourth lenses comprise:

a first portion having a third optical power; and

a second portion having a fourth optical power greater than the first optical power.