A tunable microlens uses at least two layers of electrodes and a droplet of conducting
liquid. Such a droplet, which forms the optics of the microlens, moves toward an
electrode with a higher voltage relative to other electrodes in the microlens.
When calibration of the microlens is desired, an equal and constant voltage is
passed over the first layer of electrodes and a different, constant voltage is
passed over the second layer of electrodes, which may, for example, be disposed
in a star-like pattern. A driving force relative to each electrode in the second
layer results and is proportional to the length of the circumference of the droplet
that intersects with each of the electrodes. This driving force reaches equilbrium,
and hence the droplet reaches its nominal centered position relative to the second
layer of electrodes, when the length of intersection of the circumference of the
droplet with each of the electrodes in the second layer is equal.