Unisex metal sunglasses effect

Unisex metal sunglasses can block uncomfortable glare, and at the same time protect the eyes from ultraviolet rays. All of this is due to the metal powder filter device, which can "select" the light when it hits it. Colored glasses can selectively absorb some of the wavelengths that make up the sun's rays because they use very fine metal powders (iron, copper, nickel, etc.). In fact, when light hits the lens, the light is reduced based on the so-called "destructive interference" process. In other words, when certain wavelengths of light (herein referred to as ultraviolet a, ultraviolet b, and sometimes infrared) pass through the lens, they will cancel each other out on the inside of the lens, that is, toward the eye. The overlapping of light waves is not accidental: the peaks of one wave and the troughs of the adjacent waves combine to cancel each other. The phenomenon of destructive interference depends on the refractive index of the lens (that is, the degree of deviation when light passes through different substances in the air), and it also depends on the thickness of the lens. Generally speaking, the thickness of the lens does not change much, and the refractive index of the lens varies according to the difference in chemical composition. And the sunglasses should not be in direct contact with the sun.