Basic principles of color-changing lenses

The color-changing lens is a kind of coloring agent added to the glass composition, which has selective absorption and transmission of light. It is a colorless lens without the irradiation of short-wave ultraviolet and visible light.

The light transmittance is 87%-90%, and the refractive index is 1.5-1.6. After being irradiated by ultraviolet light and shortwave light, the silver compound (silver bromide, silver iodide) in the glass decomposes into silver and halogen, making the lens darker. Color (light transmittance will gradually decrease to 50%-55% after 2-3 minutes under sunlight, and 35%-45% after one hour).

After leaving the sun, ultraviolet rays, and short-wave light, the halogen and silver elements recombine, that is, the red inner line radiation reverses the process, so that the dark color of the lens gradually returns to the original nearly colorless state. This process is an optical bleaching phenomenon. This can prevent the damage of ultraviolet rays and glare to the eyes, and can absorb part of the visible light, making the vision more comfortable.

Chromatic lenses are suitable for flat light shading and correction of low-power refractive errors. A pair of suitable chromatic lenses can combine the two purposes of corrective lenses and sunglasses, but when used for high refractive power, color structure will appear after discoloration.

Color-changing lenses show various colors depending on the colorant melted in, which can be described as various colors, colorful, gray, brown, blue, light yellow (orange) color, gradual color, liquid crystal color change, etc.