Sunglasses can protect your eyes from the glare of the light which is not comfortable. All of these is due to the metal powder filter which could be “selected” when the light comes in “. It Can selectively absorb part of tainted sunglasses for UK women band composed of sun light because it is a very fine powder with metal.
In fact, when the light shines on the lens of sunglasses with best sales,the “interference” process would be based on light which has been reduced. That means when some wavelengths of light go through the lens, the inside of the lens that is toward the direction of the eye.They will offset each other. Overlapping is not an accidental phenomenon: a form of light wave with the wave trough close together, leading to offset each other.
The refractive index of the lens of cheap sunglasses depends on the interference phenomenon (deviation degree that light from the air through different substances), also depends on the thickness of the lens. Generally speaking, lens thickness change is not big, and lens refractive index is different according to the difference of chemical composition.