The Role Of Color-changing Lenses

The chemical composition of the color-changing lens is similar to that of the ordinary lens, except that silver halide or photosensitive organic matter is added to the color-changing lens. The silver-plated lens is composed of photosensitive silver halide particles, a small amount of copper oxide and ordinary lens glass materials. When silver halide encounters sunlight, a reversible light-color conversion reaction occurs. Silver halide can absorb all the ultraviolet rays in sunlight, and then the following reactions will occur. Under the catalysis of ultraviolet light: AgX2→Ag+X2 (X is a halogen element, including fluorine F, chlorine Cl, bromine Br, and iodine I). Because silver atom particles can absorb visible light, under the catalysis of copper oxide, the following chemical reaction occurs when the lens is in a weak light state: Ag+X2→AgX2, and the lens becomes colorless again.

However, because the glass lens is curved, it is often thin in the middle and thick around the circumference, and the silver halide is evenly distributed. When the color changes, the relatively thicker part has a darker color, and the color changes unevenly, which damages the aesthetics of the lens. Resin color-changing lens is directly coated with a layer of color-changing material on the surface of ordinary resin lens, and it evenly penetrates into the surface of the lens during processing to make it evenly discolored in the sun. These color-changing glasses come in a variety of colors, and can be turned into brown and pink according to the choice of photosensitive material.

In addition to the function of filtering ultraviolet rays, the color-changing lens can also be used as sunglasses (the color becomes darker in the sun). Especially when the light is dazzling, ordinary glasses can only shrink the glasses and cannot look directly at the hot sun. Even so, the eyes are prone to dryness and fatigue, leading to long-term reduction of pupils and disorder of the refractive system of the glasses, which has a great impact on vision.

The main function of the color changing lens is to absorb ultraviolet rays, thereby protecting eyesight. Ultraviolet rays damage the human eye in many ways. It can cause abnormal conjunctival hyperplasia, corneal protein and lipid damage, and cortical cataracts in the lens. It is also easy to cause keratitis and macular disease. Now the ozone layer at high altitude is getting thinner and thinner, and the ultraviolet light content in the sun is also rising, and the damage to human eyes is much greater than before. Therefore, the color-changing lens can reduce the damage to the eyes.