Optical scientists at the University of Arizona and Georgia Tech have shown that flat, liquid crystal diffractive lenses can change their focal distance. According to Nasser Peyghambarian, researcher, the prototype developed requires manual switching in order to change focal distance, but the planned commercial version will be able to change the focal distance automatically. The lenses involve two pieces of flat glass that are placed five microns apart. The space between them is filled with liquid crystal, and the glass is coated with a layer of indium tin oxide that is 0.1 micron in thickness. This acts as a transparent electrode, transmitting move of the impinging light. The electrodes are arranged on the lens in a circular pattern via photolithography. When voltage is applied to the circuit, the orientation of the liquid crystal molecules changes rapidly as does the optical path through the lens. Prototype spectacles did not affect distance vision when they were inactive, but allowed close-up vision when activated. Commercial models are likely to be made available first to individuals who need bifocals or trifocal lenses. Industry analysts predict that dentists will welcome the new technology, since they need to switch from extremely close-up view of patients' mouths to views of more distant equipment rapidly. Three patents were licensed by the University of Arizona to the Johnson & Johnson Development Corp., the sponsor of the research. Pixel Optics has purchased the licenses to commercialize the technology.