Exploration of the Color-Changing Principle of Color-Changing Sunglasses

The color-changing principle of color-changing sunglasses mainly relies on the special chemical reaction triggered by ultraviolet rays. Its core mechanism and implementation method are as follows:

Core color-changing mechanism

Photochromic lenses contain millions of molecules of photosensitive substances such as silver halides (such as silver chloride, silver bromide). When the lenses are exposed to ultraviolet rays or strong light, these molecules undergo chemical reactions:

Photochemical reaction: Silver halide decomposes into silver atoms and halogens. The silver atoms aggregate in the form of tiny grains, causing the lens to absorb visible light and darken.

Reversibility of reaction: When ultraviolet rays disappear (such as entering the room), silver atoms recombine with halogens to form silver halides, restoring the transparency of the lens.

Dynamic adjustment: The number of changes in molecular structure adjusts dynamically with the increase or decrease of ultraviolet intensity, and the color depth of the lens is adjusted accordingly.

Technical implementation method

Glass lenses: In the early days, a process of mixing silver halide with glass materials was adopted, but due to the difference in lens thickness, it was prone to uneven discoloration.

Plastic/resin lenses: By surface penetration method, color-changing molecules are embedded inside the lens (about 150 microns deep), which is significantly superior to the traditional coating process (only 5 microns thick), ensuring uniform color-changing.

Summary of Technical Features

Fast response: The forward and reverse response speeds are extremely fast, and the lens color adjusts instantly according to the ambient light intensity.

Ultraviolet dependence: The color-changing effect is directly related to the intensity of ultraviolet rays, and temperature may affect the reaction rate (high temperature may accelerate the reduction).

Permanent reversibility: Photosensitive substances can be repeatedly decomposed and combined to achieve stable color-changing performance over long-term use.