Patent ID: 8089699

Claim:
An optical element comprising: a container including a first end face wall and a second end face wall facing each other, a side face wall connecting the first end face wall to the second end face wall, and a hermetically sealed accommodating chamber provided inside the end face walls and the side face wall; a first liquid having polarity or electrical conductivity and enclosed in the accommodating chamber; a second liquid immiscible with the first liquid and enclosed in the accommodating chamber; a first electrode and a second electrode configured to apply an electric field to the first liquid; an insulating film; a film whose wettability to the second liquid is higher than its wettability to the first liquid; and means for applying a voltage between the first electrode and the second electrode, wherein a transmittance of the first liquid is lower than a transmittance of the second liquid, a shape of an interface between the first liquid and the second liquid is changed by applying the voltage with the means for applying the voltage, and a light transmission path, a center of which is a single virtual axis passing through the first end face wall and the second end face wall and extending in a thickness direction of the container, which is a direction in which the first end face wall and the second end face wall face each other, is formed in a portion of the second liquid, the first electrode is provided on an inner surface of the first end face wall, the inner surface facing the accommodating chamber, the second electrode is provided on an inner surface of the second end face wall, the inner surface facing the accommodating chamber, the insulating film is provided on a surface of the second electrode, the surface facing the accommodating chamber, the film whose wettability to the second liquid is higher than the wettability to the first liquid is provided on a surface of the insulating film, the surface facing the accommodating chamber, and when viewed from the thickness direction of the container, an opening having a diameter a same as or smaller than a maximum diameter of the transmission path, the center of which is the virtual axis, is provided in the film provided on the surface of the insulating film.