Glasses that change color in the sun-the history of color-changing lenses
Speaking of glasses that change color in the sun, the color change is because the lens changes color.
The substrate discoloration technology was developed by Corning Company, which has a history of 50 years and is relatively mature and stable. Its advantages are mature technology and lower cost than membrane discoloration. The disadvantage is that the speed of color change reduction is slow, and the lens with higher magnification will have slight color difference (not easy to find if you don't pay attention) because the middle edge of concave lens is thin, which means the light transmittance is slightly different. The reduction rate is slow at low temperature.
The color change technology of membrane has been developed by OmniVision for 20 years, and it is also a relatively stable technology. The advantages are that the color change reduction speed is faster than that of the substrate, and the light transmittance is not affected by the thickness of the lens. The disadvantage is that the cost is higher. The reduction rate is slow at low temperature.
The principle of glasses changing color in the sun.
The color-changing lenses of sunglasses contain millions of molecules of a substance (such as silver chloride or silver halide). When there is no ultraviolet radiation, visible light can penetrate these molecules, and visible light is a general component of artificial light sources. But when exposed to the ultraviolet rays of the sun, these molecules will undergo a chemical process, which will change their shape. The new molecular structure will absorb some visible light, thus darkening the lens. The number of molecules whose shape changes will change with the change of ultraviolet intensity.
Decolorization lens
When you come indoors and leave ultraviolet radiation, there will be corresponding chemical reverse changes. When they suddenly leave the ultraviolet radiation, these molecules will quickly return to their original structure, thus losing the characteristics of absorbing light. Whether it is a positive change or a negative change, the whole process happens very quickly.