Patent ID: 7697213

Claim:
An optical element comprising: a container having a holding chamber; a polar or conductive first liquid filled in the holding chamber; a second liquid filled in the holding chamber and not mixing with the first liquid; first and second electrodes for applying an electric field to the first liquid; and voltage application means for applying voltage between the first electrode and the second electrode, wherein a change of a position subject to the voltage application by the voltage application means to the first and second electrodes moves the first liquid in the second liquid within the holding chamber; the holding chamber has an adjustment chamber adjusting an amount of transmitted light based on a presence of the first liquid and multiple lay-by chambers connecting to the adjustment chamber and allowing the accommodation of the first liquid laid by from the adjustment chamber; the adjustment chamber and the multiple lay-by chambers have first and second end walls facing against each other in a direction that the light passes through; and the first electrode is provided on one end wall of the first and second end walls of the adjustment chamber and multiple lay-by chambers, and the second electrode is provided on the other end wall of the first and second end walls, the voltage application by the voltage application means to the first and second electrodes causes the first liquid in the holding chamber to be divided such that a mass and travel of each portion of the divided first liquid is reduced as compared to a mass and travel of the entire non-divided first liquid so that a speed of movement thereof is increased.