Patent ID: 7325922

Claim:
Adjustable focus eyeglasses comprising: A) two lens units, each lens unit comprising a first lens element and a second lens element, and each lens element having a specially designed thickness profile wherein the designs of the thickness profiles are chosen such that small adjustments of the relative positions of the two lenses in directions perpendicular or approximately perpendicular to a viewing direction results in changes in the combined focus of the two lenses of the lens unit; B) an eyeglasses frame system for holding said lens elements, said frame system comprising an adjustment mechanism for adjustment of the position of at least one of the two lens elements relative to the other in a direction generally perpendicular to a viewing direction; wherein the thickness profiles are approximately given by the following three equations defining a thickness profile function for each of the two lens elements: ((α v+ 1) −2 ∂ 3 t/∂u 3 +α(α v+ 1) −1 ∂ 2 t/∂v∂u )| (u,v)=(0,0) =2 A (∂ 3 t/∂v 2 ∂u )| (u,v)=(0,0) =2 A ((α v+ 1) −1 ∂ 3 t/∂v∂u 2 −α(α v+ 1) −2 ∂ 2 t/∂u 2 )| (u,v)=(0,0) =0, where A for one lens element to be the complement, or substantially the complement, of the other lens element and where the thickness profile functions continuous, and the derivatives up to at least third order are continuous.