Multicoated

Multicoated refers to surfaces that have two or more coating layers applied to improve functional properties, typically in optics, protective finishes, or electronics. In optics, multicoating is most often used to reduce reflection and increase light transmission at selected wavelengths, while protecting the underlying substrate.

Multilayer coatings are usually dielectric stacks consisting of alternating high- and low-refractive-index materials. By carefully choosing materials and layer thicknesses, the coating produces destructive interference for reflected light while preserving or enhancing transmission for desired wavelengths. Some coatings combine dielectric layers with a metal layer to tailor reflectivity and durability.

Common applications include anti-reflective coatings on eyeglass and camera lenses, telescope optics, microscope objectives, and sensor covers, as well as protective or functional coatings on solar cells, displays, and precision instruments. Benefits include higher transmission, reduced glare, better color fidelity and contrast, and increased surface hardness and chemical resistance.

Performance depends on wavelength band, angle of incidence, and environmental exposure. Real-world results vary by manufacturing quality and deposition method, such as vacuum evaporation, sputtering, or chemical vapor deposition. Multicoated products should be maintained with gentle cleaning and avoided with harsh solvents, and specifications typically report transmittance, reflectance, and operating range to guide selection.