Patent ID: 7385765

Claim:
An optical element, comprising: a sealed container having a first end wall facing a second end wall in a thickness direction, and a sidewall connecting the first and second end walls; a first polar or conductive liquid encapsulated in the container; a second liquid encapsulated in the container and not mixed with the first liquid so as to form an interface between the first liquid and the second liquid, the first liquid and the second liquid having substantially the same specific gravity and the first liquid having less light transmittance than the second liquid; voltage application means for applying a voltage to the first liquid, the voltage application means including a first electrode provided on the first end wall, at least part of the first electrode facing the inside of the container, a second electrode provided on the second end wall, at least part of the second electrode facing the inside of the container, and an insulating film covering the part of the second electrode facing the inside of the container, a first film formed on the entire inner surface of the first end wall, on the part of the first electrode facing the inside of the container, and on the entire inner surface of the sidewall, the first film having a higher wettability to the first liquid than to the second liquid; and a second film formed on the entire inner surface of the second end wall, on the part of the second electrode facing the inside of the container, and on the insulating film, the second film having a higher wettability to the second liquid than to the first liquid, wherein when a voltage is applied to the first liquid, the interface between the first liquid and the second liquid deforms to form a light transmission path that passes through the first and second end walls and extends in the thickness direction of the container, and when no voltage is applied to the first liquid, the second liquid is positioned against the second film, while the first liquid entirely extends in a direction perpendicular to the light transmitting direction and an outer periphery of the first liquid that faces the inner surface of the sidewall is positioned over the second electrode via the second film and the insulating film.