Patent attributes
A variable focus lens includes a ring with a front surface and a rear surface. A flexible membrane is held between the front surface of the ring and a generally rigid transparent front cover, and a rear cover is attached to the rear surface of the ring, optionally with a second flexible membrane sandwiched between the rear cover and the ring. A cavity is formed between the flexible membrane and the rear cover or the second flexible membrane is filled with a liquid, and the amount of fluid in the cavity can be varied to vary the curvature of the flexible membrane and so vary the optical characteristics of the lens. The ring of the lens may be coloured, and may be transparent, translucent or opaque. Alternatively, a decorative cover may be attached to the front of the ring to give the appearance of a frame. The lenses may be used in variable focus spectacles.
