Color Changing Sunglasses

Many car drivers often wear a pair of black glasses while driving. When driving a car in the sun or snow, this pair of black glasses can protect the eyes from being stimulated by strong light for a long time. However, when the car suddenly drove from the bright place to the dark place, wearing black glasses became a burden instead. Wearing it for a while and taking it off for a while is really inconvenient. Is there any good way to relieve the distress of the driver? have. Wearing color-changing glasses will do. In the sun, it is a pair of black sunglasses, and the thick black glass lens blocks the dazzling light. In a room with soft light, it becomes transparent and colorless like ordinary glasses.

The mystery of color-changing glasses is in the glass. This particular glass is called "photochromic" glass. In the manufacturing process, it is pre-doped with light-sensitive substances, such as silver chloride, silver bromide (collectively referred to as silver halide), etc., and a small amount of copper oxide catalyst. The spectacle lenses change from no color to light gray, tea brown, and then from black glasses to Yintong glasses, all of which are silver halide magic.” In the glass of color-changing glasses, there is a change very similar to the exposure and imaging of photosensitive film The process. Silver halide decomposes when it sees light, and turns into many black silver particles, which are evenly distributed in the glass, so that the glass lens appears dim and blocks the passage of light. This is black glasses. However, it is different from the situation on photosensitive film , the silver atoms and halogen atoms formed after the decomposition of silver halide are still close together. When returning to a slightly darker place, under the promotion of copper oxide catalyst, silver and halogen recombine to form silver halide, glass lens It became transparent again.

Silver halide is permanently resident in the glass, and the reactions of decomposition and compounding are repeated endlessly. Photographic film and printing paper can only be used once, but photochromic glasses can be used forever. Color-changing glasses can not only darken and brighten with the intensity of light, but also absorb ultraviolet rays that are harmful to human eyes. They are indeed top-grade glasses. If all the window glass is replaced with photochromic glass, the sunlight will not shine into the room on sunny days; on cloudy days or in the morning and evening, the outdoor light will not be blocked, and the room will still be bright. It's as if automatic sun-shading curtains are hung on the windows. In some high-end hotels and restaurants, color-changing glass has been installed. This kind of photochromic glass is installed on the cab of the car and the window of the tourist bus. Under the direct sunlight, even the color-changing glasses are not needed. What joy!