Phys.org August 9, 2019
Over 2,000 years ago, Greek scientist Diocles recognized a problem with optical lenses—when looking through devices equipped with them, the edges appeared fuzzier than the center. He proposed that the effect occurs because the lenses were spherical so that light striking at an angle could not be focused because of differences in refraction. Most such efforts have involved creating aspherical lenses to counteract refraction problems. And while they have resulted in improvement, the solutions have generally been expensive and inadequate for some applications. Researchers in Mexico have found a way of fixing the problem with any size lens based on describing ways in which the shape of a second aspherical surface needs to be given a first surface, along with object-image distance. In essence, it relies on a second surface fixing problems with the first surface. The result is elimination of spherical aberration. Once the math was established, the researchers tested it by running simulations. They report that their technique can produce lenses that are 99.9999999999 percent accurate. The researchers suggest the formula can be used in applications including eyeglasses, contact lenses, telescopes, binoculars and microscopes…read more. Open Access TECHNICAL ARTICLE
(a) Geometry of the problem and notation used for the distances. The origin of the coordinate system is located at the center of the input surface z a 0, 0† ˆ 0. (b) Zoom showing the notation for the unit vectors.