Method and apparatus for auto-focus using liquid crystal adaptive optics

A system for electronic auto-focus, comprising:

• a lens;
• a sensor for detecting an image from the lens;
• a first liquid crystal layer between the lens and the sensor for passing waves in two orthogonal polarizations and for electronically adjusting a refractive index for extraordinary (p) waves;
• a second liquid crystal layer between the lens and the sensor for passing waves in two orthogonal polarizations wherein the optical axes of the first liquid crystal layer and the second liquid crystal layer are orthogonally aligned in construction through a surface treatment of a liquid crystal substrate for the first and second liquid crystal layers and wherein the first liquid crystal layer and the second liquid crystal layer are flat surface liquid crystal elements;
• and
• a controller programmed to change external voltages applied to the first liquid crystal layer and the second liquid crystal layer to alter the optical path through each liquid crystal layer using feedback from an auto focusing processor, such that the optical path of the first liquid crystal layer and the second liquid crystal layer for two orthogonal polarized lights are identical.

A method for auto-focusing, comprising the steps of:

• capturing an image through a lens and a sensor;
• and
• orthogonally phase modulating a first liquid crystal layer and a second liquid crystal layer that reside between the lens and the sensor, wherein the first liquid crystal layer and the second liquid crystal layer pass waves in two orthogonal polarizations and are flat surface liquid crystal layers;
• and
• electrically adjustinq a refractive index for extraordinary (p) waves using the first liquid crystal layer and the second liquid crystal layer respectively such that the optical path of the first liquid crystal layer and the second liquid crystal layer for two orthogonal polarized lights are identical.