A first liquid and a second liquid are sealed in a cell, and the first liquid and the second liquid are not mixed with each other, and have different refractive indexes, with the interface of the two liquids being remained stationary by an edge portion of a movable opening member that is made in contact with the interface of the two liquids so that an actuator that is coupled to the movable opening member controls a shape of the interface of the two liquids by driving the movable opening member.