The science of color-changing glasses

Color-changing glasses are a kind of special glasses that can automatically change color according to the intensity of light. Here are some popular science knowledge about it:
How it works:
The lenses of color-changing glasses contain a special light-sensitive material, such as silver halide. When ultraviolet light hits the lens, silver halide breaks down, creating silver atoms and halogen ions that darken the lens. When the ultraviolet light disappears, the silver atoms recombine with the halogen ions, and the lens returns to a transparent state. This change is automatic and reversible.

Discoloration performance:
Color change speed: high-quality color-changing glasses change color faster, generally within a few seconds to tens of seconds to complete the color change. For example, in the outdoors, from a bright environment into a strong light environment, the lens can quickly darken. Indoors, when the light is weak, the lens can also be restored to transparency in a relatively short time.
Color selection: The common color of color-changing glasses are gray, brown, pink, light blue, green, yellow and so on. Different colors of the lens have different functional characteristics, for example, the gray lens can absorb a variety of colors evenly, will not make the scene color change due to the lens, can effectively reduce the intensity of light; Brown lens can filter out a lot of blue light, improve visual contrast and clarity, suitable for drivers; The pink lens has a better absorption function of ultraviolet light, which can reduce the overall light intensity and make it more comfortable to wear.
Suitable for people: people who often switch between indoor and outdoor environments, such as people who often go out for travel, outdoor activities or work (mountaineers, sanitation workers, traffic police who direct traffic, etc.), as well as patients after cataract surgery are more suitable for wearing color-changing glasses.

Not applicable to:
The physiological mechanism of children going to school is not yet mature, can not accurately adjust the parallax, wearing color-changing glasses to see the words on the blackboard may be laborious, fuzzy, premature damage to the eyes.