Anti-reflective (AR) Coating
Anti-reflective coating (also called AR coating or anti-glare coating) is a microscopically thin multilayer coating that eliminates reflections from the front and back surfaces of eyeglass lenses.
By doing so, AR coating makes lenses nearly invisible so people focus on your eyes and not distracting reflections. AR coating also eliminates glare caused by light reflecting from lenses. With reflections eliminated lenses with AR coating provide better vision for night driving and more comfortable vision for reading and computer use. AR coating is recommended for all lens materials, but particularly for polycarbonate and hi index lenses which are the most reflective. It is beneficial when applied to the back surface of sunglasses to eliminate ‘’bounce-back’’ reflections when facing away from the sun.
For the best possible comfort in all lighting conditions many eye care professionals recommend applying AR coating to photochromic lenses. AR coating improves light transmission through the lenses for night driving and helps reduce glare in bright sunlight.
The Power Vision products use a technique known a magnetron sputtering to produce the thin multilayer coating required for producing AR coatings.
Magnetron sputtering has a number of advantages over conventional physical vapour deposition techniques such as electron beam and thermal evaporation for the application of thin coatings. For example, the kinetic energy of the sputtered atoms is typically 10 times higher than that of evaporated species, this results in much harder and much more adherent coatings. The energy of the process also removes the need for substrate heating during deposition which is of specific benefit when coating plastic substrates or other temperature sensitive substrate materials. This means that deposition is carried out at room temperature allowing different materials such as glass and plastic to be coated even in the same batch. Compact magnetron sources are also capable of high deposition rates which result in fast process cycle times.