Sunglasses factory, also known as sunshade glasses, are used for sunshade. People usually adjust the luminous flux by adjusting the pupil size in the sun. When the light intensity exceeds the adjustment ability of the human eye, it will cause damage to the human eye. Therefore, in outdoor activities, especially It is in summer that sun visors need to be used to block the sun to reduce the fatigue caused by eye adjustment or the damage caused by strong light stimulation.

Sunglasses can block uncomfortable strong light, and at the same time can protect the eyes from UV damage. All this It's all thanks to metal powder filters that "select" light as it hits it. Tinted glasses selectively absorb some of the wavelengths that make up the sun's rays, thanks to the help of very fine metal powders (iron, Copper, nickel, etc.)

In fact, when light hits the lens, the light is eliminated based on the so-called "destructive interference" process. That is, when light of certain wavelengths (here refers to ultraviolet a, Ultraviolet rays, and sometimes infrared rays) pass through the lens, and they cancel each other out on the inside of the lens, in the direction of the eye. The overlapping of the resulting light waves is not accidental: the crests of one wave merge with the troughs of the waves that are close together. , resulting in mutual cancellation.

The phenomenon of destructive interference depends on the refractive index of the lens (that is, the degree to which light deviates when passing through different substances from the air), and also on the thickness of the lens. Generally speaking, the thickness of the lens does not change much , and the refractive index of the lens is different according to the difference in chemical composition. And sunglasses can not directly contact the sun.