Color-changing lenses are used in car windows, knockoff Ray Ban sunglasses, and visual display units (visual display unit), and their basic components are halogen materials. Japanese researchers have developed a light-sensitive lens that can be recycled. The composition of this new ecological lens (ecoglass) does not contain such environmentally damaging halogen (chlorine, bromine, iodine) materials. This research has been published. In the latest issue of Chemical Communications.

Like photographic film, today's photosensitive lenses darken because they contain silver and halogen compounds such as silver iodide. Ultraviolet rays in sunlight provide enough energy to move some of the electrons contained in the halide ions, and these electrons combine with the silver ions to become neutral atoms of metallic silver. These silver atoms then aggregate into tiny particles that scatter light away and darken the lens.

However, the above process is reversible, some sunglasses will return to clear within minutes after being kept away from ultraviolet light, while others must be heated to restore their original shape. During each recovery, electrons are detached from the silver atoms, causing their metal clusters to subdivide into silver ions again.

Halogens react with carbon-based molecules to form toxic and carcinogenic compounds. In order to replace halogens, Tetsuo Yazawa of the Osaka Institute of Industrial Technology (AIST) and colleagues added silver ions in the form of silver nitrate. Completely mixed in standard lens stock.

Lenses made of silver nitrate will turn from transparent to yellow under UV light, and when the yellowed lenses are heated at 500°C for 15 minutes, they will return to transparent again. The change of this lens from clear to yellow and back to its original color can be repeated countless times.

For some applications, a wider spectrum is necessary, but researchers have yet to develop lenses that can change to other colors, and all color changes are the result of minutes of exposure to UV lasers, not Through natural light. However, this new material shows that in the process of color change, halogen is not necessary. And this research also points out that the new material developed may contribute to more high-tech applications of "optical memory" devices (repeatedly "printing" information onto optical memory devices through laser energy).

It is derived from the Internet word "bright". "Bright" is used to describe someone's content that is bright, humorous, shocking, etc. Sunglasses are things that block light and shine. When someone publishes content that is too connotative and amazing, it is too bright to resist even sunglasses, and even to the extent of shattering, everyone exclaimed: My sunglasses are broken! It refers to the equipment used to resist dazzling objects and prevent your glasses from being blinded. Later, alloy sunglasses, high-strength tempered glass sunglasses, etc. were derived, and the usage was similar.

Polarized fake Ray Ban sunglasses provide another mechanism for eye protection. The reflected light of the asphalt road is a relatively special polarized light. What differentiates this reflected light from light coming directly from the sun or any artificial light source is the order. Polarized light is formed by light that vibrates all in one direction, while normal natural light is formed by light that vibrates in all directions. It's a stark contrast between a group of people walking around in disorder and a group of soldiers marching in neat steps. Generally speaking, reflected light is an ordered light. Polarized lenses are especially effective at blocking this light because of its filtering properties. The lens only lets through polarized waves that vibrate in a certain direction, as if "combing" the light. For road reflection problems, using polarized glasses can reduce the transmission of light, because it does not allow light waves that vibrate parallel to the road to pass. In fact, the long molecules of the filter layer are directed horizontally and can absorb horizontally polarized light. In this way, most of the reflected light is eliminated without reducing the overall illumination of the surrounding environment.