Switchable diffractive lens for vision correction

New switchable, flat, thin liquid crystal diffractive lenses have been introduced that offer stringent requirements including high light efficiency, relatively large aperture, fast switching time, low driving voltage, and power-failure-safe configuration. Lenses with eight phase levels, 10 mm diameters, and focal length of 1m and 0.5m have been demonstrated at 555nm. The lens operate with high transmission, low voltage, fast response, a diffraction efficiency exceeding 90%, small aberrations, and a power-failure-safe configuration. Negative focusing powers can also be obtained with the same lenses by changing the sign of the slope of the applied voltages. These represent a significant advance in the state-of-the-art in liquid crystal diffractive lens for vision care and other applications and also have the potential of revolutionizing the field of presbyopia correction.