Patent ID: 7548363

Claim:
An optical element comprising a closed cell, containing a first fluid and a second fluid, wherein the first fluid is conductive and the second fluid coloured and immiscible with the first fluid, a first electrode, covered with a first hydrophobic, insulating layer and located at a first wall the cell, a voltage between the first electrode and the first fluid being controllable in order to control an area of the first hydrophobic layer that contacts the first fluid, and thereby an amount of light that is transmitted through the cell in a direction perpendicular to the first wall, wherein the cell comprises a second electrode covered by a second hydrophobic, insulating layer, and the optical element comprises means for applying a voltage between the first fluid and, alternately, the first electrode or the second electrode, wherein the first electrode is planar and parallel with the first wall, and wherein the second electrode extends substantially perpendicular to the first electrode.