US Patent 7245440 Variable focal lens

A variable focus lens comprises a chamber containing a conductive liquid (5) and an insulating liquid (4) of different refractive indices, the surface of contact between the two liquids forming a deformable refractive surface (6) whose periphery is caused to move along the walls of a housing under the effect of an electric voltage (V). The housing comprises an upper portion (16) inclined relative to a plane perpendicular to the optical axis (Δ) of the lens, a lower portion (34, 48, 52) more inclined than the upper portion and a zone of junction (B′) between the upper and lower portions, playing the role of a stop for the deformable refractive interface.