How do optical lens manufacturers make optical lenses? (3)
(3) Stained glass materials: optical lens manufacturers will show the coloring effect after mixing some metal salts with special absorption properties into the glass materials. Fruit, for example: add nickel and cobalt (purple), cobalt and copper (blue), chromium (green), iron, cadmium (yellow), gold, copper and selenium (red), etc. These stained lens materials are mainly used to produce flat lenses or protective lenses on a large scale. Some light colored materials (brown, gray, green or pink) with special filter properties are also used to produce refractive correction lenses.
(4) Photochromic glass materials: photochromic phenomenon is a property of changing the light absorption properties of materials to make the materials respond to the intensity of sunlight. optical lens manufacturers aim to darken ordinary glass (including plastic photochromic materials) by UV radiation and darken it by ambient heat, two processes that are reversible and may always be present. This phenomenon is achieved by excitation. By living in a mixture of photochromic molecules in the material. The first appeared in 1962. The properties of secondary photochromic glass materials have been improved continuously since then. optical lens manufacturers mainly add silver halide crystals to the glass material. The crystals react under ultraviolet radiation, darkening the lenses.
Primary and secondary photochromic glass material color change principle is a kind of electron exchange between silver atom and chlorine atom, through the silver chloride and the surrounding environment. optical lens manufacturers in the absence of light conditions, silver chloride is ionic, silver ion is transparent, so the lens is transparent; Under ultraviolet radiation, the unstable electrons leave the chloride ions, combine with the silver ions and absorb light, and the lens deepens. As the UV radiation wanes, the moving electrons leave the silver atoms and return to the chlorine atoms, and the lens gradually returns to its original clear state. To general photochromic glass, discoloration is also controlled by temperature at the same time, when the illuminance is unchanged, the lower the temperature, the darker the color. Photochromic materials are mostly gray and brown, commonly known as gray and tea, but other colors can also be achieved by special processes. All lenses, including melted bifocal lenses and progressive lenses, can be manufactured using photochromic materials. In recent years, with the rapid development of photochromic resin lenses and the continuous improvement of materials, the refractive index is no longer limited to 1.50.
