When anti-reflective lens coating is applied, what is the thickness of the coating?

The thickness of an anti-reflective lens coating is designed to be specifically one-quarter of the wavelength of the incoming light. This thickness is critical because it allows for destructive interference of light waves that reflect off the surface of the lens. When light hits the lens, some light will reflect off the top surface of the coating, while some light penetrates the coating and reflects off the lens surface beneath it.

By setting the thickness of the coating to one-quarter of the wavelength of the incoming light, the reflected waves from the top surface and the lens surface are out of phase with each other by 180 degrees, causing them to cancel each other out. This results in a significant reduction of reflected light, which enhances clarity, contrast, and overall visual quality for the wearer.

This principle of interference is a fundamental aspect of optics and is crucial for maximizing the benefits of an anti-reflective coating on lenses.