The types of lenses are roughly divided into five types: anti-reflective protective lenses, colored lenses, color-coated lenses, polarized lenses, and color-changing lenses.
anti-reflective protective lens
This lens is coated with a thin layer of magnesium fluoride to prevent strong light reflection, making you see things more clearly and not subject to strong light. To check if your glasses are really anti-reflective lenses, point the glasses at the light source. If you see a purple or green reflection, it means that there is indeed an anti-reflective protective film on the lens.
Also known as "dyeing lens", in the lens manufacturing process, adding some chemicals to make the lens color to absorb light of a specific wavelength. This is the type of lens most commonly used in sunglasses.
This kind of lens presents the same effect as a colored lens. It is only made in a different way. It is applied to the surface of the lens. The most well-known is the "gradient coating lens", the color is the deepest, then down Gradually. Generally, sunglasses with degrees are mostly processed by coloring.
In order to filter the glare of the sun in the equal direction on the surface of the water, land or snow, a vertical special coating is added to the lens, which is called a polarized lens. Ideal for outdoor sports such as sea activities, skiing or fishing.
Also known as "photosensitive lens." Because the silver halide chemical is added to the lens, the original transparent and colorless lens will become a colored lens when it is exposed to strong light, so it is suitable for indoor and outdoor use.