Patent ID: 8197062

Claim:
A variable focus lens system for use in eyeglasses, comprising: (a) a first lens element, fixed to a frame, one side of said first lens element being divided into a plurality of first fresnel zones and at least one first zone boundary of the first fresnel zones; (b) a second lens element, superimposed in tandem on said first lens element along the optical axis of the system, said second lens element being relatively slidable in a direction normal to the optical axis of the lens system, one side of said second lens element being divided into a plurality of second fresnel zones and at least one second zone boundary of the second fresnel zones; (c) a prescription lens, for providing user's distance and astigmatism correction, and for protecting the first and second lens elements from dust and impacts, the prescription lens being superimposed on said first and second lens elements, the second lens element being medial the first lens element and the prescription lens; (d) said one side of said first lens element, having a plurality of first fresnel zones and at least one first zone boundary, being directed toward the second lens element; (e) said one side of said second lens element, having a plurality of second fresnel zones and at least one second zone boundary, being directed toward the prescription lens; and (f) means for moving said second lens element relative to said first lens element in a direction normal to the optical axis of the lens system.