Researched
Anti-Reflection Coatings
A thin film a quarter-wavelength thick cancels reflections from a lens surface; Smakula's 1935 patent at Zeiss makes many-element lenses practical.
Open in the interactive tree →Each uncoated glass surface reflects about 4 % of light, which adds up in lenses with dozens of elements. Alexander Smakula at Zeiss patented interference coatings in 1935, and they are standard on cameras, binoculars and chip-lithography lenses.