摘要 |
The invention relates to a variable-focus lens (60) for focussing light rays in light paths passing through the lens along an optical axis (&Dgr;). The lens comprises an arrangement of first and second immiscible liquids (67, 68) that have different refractive indices and are in contact over a moveable refractive optical interface (69), a volume of gas (72) in contact with one of said liquids, and a retention measure (70, 74) for keeping the volume of gas away from the light paths of the light rays passing through the lens for focussing. |