Patent ID: 7218429

Claim:
A Digital Focus Lens System for providing an optical system having a plurality of selectable focal powers, comprising: a first switchable element capable of being switched between a first-element first-state and a first-element second-state; and and a second switchable element capable of being switched between a second-element first-state and a second-element second-state; wherein the first and second switchable elements are in optical communication with each other such that each of them may contribute to a cumulative focal power, wherein, a first focal power may be selected by activation of the first switchable element to the first-element first-state and activation of the second switchable element to the second-element first-state, wherein a second focal power may be selected by activation of the first switchable element to the first-element second-state and activation of the second switchable element to the second-element first-state, wherein a third focal power may be selected by activation of the first switchable element to the first-element first-state and activation of the second switchable element to the second-element second-state, and wherein a fourth focal power may be selected by activation of the first switchable element to the first-element second-state and activation of the second switchable element to the second-element second-state; wherein each of the first, second, third and fourth focal powers is unique, wherein the values of the selectable focal powers follow a linear progression such that the difference of the first and second focal powers, the difference of the second and third focal powers, and the difference of third and fourth focal powers are substantially identical.