Sunglasses are a kind of protective glasses, human invention of sunglasses has a history of 2,000 years, the ancient Romans with colored glass to cover the eyes to reduce sunlight stimulation, is the earliest prototype of sunglasses. With the continuous progress of social civilization, the fashion attributes of sunglasses are increasingly valued by most people, in the eyes of many young people, sunglasses represent the language of summer, the sun’s landscape. In fact, the most fundamental role of sunglasses is to provide radiation protection for the eyes. In nature there are many light that can cause harm to the human eye, mainly ultraviolet light, strong visible light and infrared. Among them, ultraviolet light is the most harmful to the human eye, long-term absorption of ultraviolet light on the eye cornea, crystal, retina, etc., will have a destructive effect, will lead to photochemical keratopathy, cataract, retinopathy and other eye diseases. So people who often work or live in a bright light environment, it is necessary to wear a pair of sunglasses to provide radiation protection for the eyes. Sunglasses can be classified as absorbing, reflecting, polarizing and interfering according to their principle. Absorption filters are usually achieved by adding metal oxides to the lens, such as: iron oxide, cobalt oxide, chromium oxide, etc. These oxides can absorb ultraviolet and infrared radiation; reflective filters are made by coating the surface of the lens with a metal film layer, which mainly reflects infrared light and has poor protection against ultraviolet radiation; polarization filters can filter out 98% of the reflected light and 96% of the ultraviolet radiation through the polarization layer. Interferometric filters filter radiation by changing the wavelength of light through multiple layers of electrically insulating film. In addition sunglasses according to other ways can be classified as follows, according to the lens color: gray system, teal system, green system, blue system, mercury system, yellow system, etc.; frame material: metal, plate; according to the lens: dye type, color change type, clip type, set of mirror type; according to the lens design: monochrome, gradient color.