As light passes through an uncoated glass substrate, approximately 4% will be reflected at each interface. Antireflection coatings, also known as AR coatings, are a type of coating used on mirrors, lenses and other optical components to minimize the back reflection from the optic. In typical imaging systems, this improves efficiency because less light is lost. In other optical systems, such as telescopes, antireflection coatings also improve image contrast by elimination of stray light. Other examples include anti-glare coatings on corrective lenses and camera lens elements, and antireflective coatings on solar cells.