Patent ID: 7327523

Claim:
An optical element, comprising: an airtight container having opposing first and second end face walls in a thickness direction, and side walls connecting the first and second end face walls; a first liquid sealed in the container and having polarity or conductivity; a second liquid sealed in the container and not mixed with the first liquid so as to form an interface between the first liquid and the second liquid; and voltage applying means for applying a voltage to the first liquid, wherein the first liquid and the second liquid have substantially the same specific gravity, and the first liquid has less light transmittance than the second liquid, in a state in which the voltage is applied to the first liquid, the interface between the first liquid and the second liquid deforms, and a transmitting path of light is formed that passes through the first and second end face walls and propagates in the thickness direction of the container, a first film is formed over the entirety of an inner surface of the first end face wall, the wettability of the first film with respect to the first liquid being higher than the wettability of the first film with respect to the second liquid, a second film is formed over the entirety of an inner surface of the second end face wall, the wettability of the second film with respect to the second liquid being higher than the wettability of the second film with respect to the first liquid, the voltage applying means includes a first electrode provided on the first end face wall, and a second electrode provided on the second end face wall, and in a state in which the voltage is not applied to the first liquid, the second liquid is located on the second film, and the first liquid extends over the entire region of a direction orthogonal to a light transmitting direction.