Antireflektif

Antireflektif refers to surfaces or coatings designed to minimize optical reflections in order to maximize transmittance and reduce glare. It is widely used on lenses, displays, and solar cells to improve visibility, contrast, and overall efficiency of optical systems.

The basic principle is thin-film interference. A coating with carefully chosen refractive indices and thicknesses causes light reflected from the air–coating and coating–substrate interfaces to interfere destructively, reducing the net reflected light. A single quarter‑wave layer targets a specific wavelength, while broadband performance uses multiple layers with alternating indices or gradient-index structures. In addition, nano‑patterned or moth‑eye-like surfaces can suppress reflections across a broad range of wavelengths and viewing angles without distinct spectral features.

Materials and methods commonly used for antireflektif coatings include dielectric layers such as magnesium fluoride (MgF2), silicon dioxide (SiO2), and higher-index materials like titanium dioxide (TiO2) or tantalum pentoxide (Ta2O5). Coatings are deposited by physical vapor deposition, sputtering, chemical vapor deposition, or sol-gel processes. Emerging approaches include gradient-index coatings and sub-wavelength surface textures that provide low reflectance over wide spectral ranges.

Applications span eyeglasses and camera lenses, smartphone and display screens, telescope optics, solar panels, and various optical sensors. Antireflektif coatings improve transmitted light, contrast, and color fidelity, while reducing stray reflections that can cause ghost images.

Limitations include sensitivity to incidence angle, wavelength range, and environmental wear. Durable, broadband AR coatings tend to be more complex and costly, and some coatings require protective overcoats or careful cleaning to maintain performance.