antirefleks

Antirefleks, or anti-reflective coating (AR coating), is a dielectric thin-film coating applied to optical surfaces to reduce reflections and increase transmitted light. By minimizing glare, these coatings improve contrast, color fidelity, and overall optical efficiency for lenses, displays, and other optics.

The coating works by using thin-film interference. A layer or stack of layers with carefully chosen refractive indices causes reflected light waves to cancel each other out at the surface, allowing more light to pass through. A simple, single-layer coating often uses magnesium fluoride on glass, while more robust performance across a broad spectral range is achieved with multiple alternating high- and low-index materials designed for a specific bandwidth and incident angle.

Common materials for AR coatings include magnesium fluoride (MgF2), silicon dioxide (SiO2), titanium dioxide (TiO2), tantalum oxide (Ta2O5), and hafnium oxide (HfO2). Designs vary from narrowband to broadband and from normal-incident to wide-angle coatings. The choice of materials and layer thicknesses determines the level of reflectance reduction, the spectral range, and the color tint visible on coated surfaces.

Applications are widespread and include eyeglasses, camera lenses, telescopes, microscopes, displays, and solar panels. Manufacturing typically involves vacuum deposition methods such as electron-beam evaporation or sputtering, sometimes with ion-assisted deposition to improve durability. Many AR coatings are combined with protective hard coats or hydrophobic top layers to enhance scratch resistance and moisture resistance.

Limitations include sensitivity to abrasion, environmental exposure, and angle of incidence. Broadly effective, durable AR coatings continue to be a focus of optical engineering, balancing reflectance reduction, durability, and cost.