Myopia polarized sunglasses can choose which quality?

Choose a pair of lightweight solid sunglasses can in sorching summer is the escort of your eyes, the fashionable modelling is the icing on the cake for you. What then shall we choose the material of the glasses? Recommended reading: photo three necessary personality lenses material: resin: resin PC lenses are so common and ordinary resin lens PC lens: PC is polycarbonate. The density of polycarbonate is 57% lighter than the glass lenses, 37% lighter than the ordinary resin lens; Its toughness is very strong, not easy and broken, very suitable for children and go. Coupled with its high refractive index, so the PC lens can be very thin. Another PC lens itself has the ability of uv protection, it does not need to like glass membrane, can prevent 100% of ultraviolet light. But has its drawbacks as well as the PC lenses, because of its strength than glass, so don't wear, need to add membrane to ensure long time use; Soft and quality of a material is glass, deformation, easy on wu kuang is not suitable for plastic frames and frame. High refractive index also lead to lower the abbe number ( Generally around 32) , dispersion is bigger. CR- 39 lenses: ordinary resin lens CR - generally refers to the United States 39 resin lenses. Abbe number is higher, the relatively small dispersion, density is a little higher than PC, but still a lot lighter than the glass, not easily broken, even if broken also won't produce sharp horns. The refractive index is lower, generally in 1. Five or so, so the lens is thick. Glass lenses: glass lenses are the first to use the lens, its quality of a material is hard, not easy deformation, not easy to change color, compared with PC and resin is not easy scratches, can be changed by adding different material glass refractive index, ordinary glass lens refractive index is approximately 1. 523. Weakness is heavier, resin lens is almost twice as heavy, fragile, once broken easily scratch the eye, so now is one of the few glass lenses, are made of resin lenses. MR lens: MR lens is the most balanced performance index of high refractive index lens materials, especially suitable for production of glasses. Lens frivolous, clear vision, high pressure, the lens is not easy to damage, the most important thing is that compared with ordinary lens, not easy to become yellow, clear and bright for a long time, the corrosion resistance is very good. Nylon lenses: nylon lenses should be relatively new technology, has a close physical strength and optical properties of CR39 of PC, and light weight, is the ideal material, but prices higher than the PC. Lens film: whatever the lens will have shortcomings, and in order to improve the optical properties of the lens will need to coating on the lens. According to the function of the membrane, common by epidural, fight corrupt film, polarizing film, UV resistant film as well as by a variety of film composed of multilayer film and so on. Points are mainly from the color green, blue, red, green wait for color. The color of the membrane and membrane function and no specific corresponding relation, don't need to care about film color. Blue is a cool color, red is warm color, green is a neutral color, so generally people psychologically for green film is more adaptive, green film lens will be relatively comfortable ( Is merely from the psychological point of view) 。 Add epidural also calls the wear resistance of membrane, reduce the degree of lens scratches, generally glass lenses can not plated with epidural, but resin lens must be plated to epidural. Anti-fouling membrane can not only reduce mirror surface stains, can waterproof, prevent mist, dust and so on pollution prevention. There is a film called 'back AR reduced reflective film plating', is near the side of eyes, role is to prevent double. Reduce from the glasses back into the light caused by the reflection, make the light from the mirror back to the front of the mirror, reduce the reflection to the eyes, greatly improve visual clarity, wearing effect is remarkable. Although some film can play a role hardening on the surface of the lens, but it is still very delicate, in use process need to be careful. And any film is, the service life of the lens membrane is damaged, the basic equal to the lens scrap. UVUV is ultraviolet (uv) light. Uv is the essential function of sunglasses, it has nothing to do with the lens color and light transmittance, usually by coating, usually use the following three kinds of express way. Labeled 'UV400' : it means the lens to block below the wavelength of 400 nm uv and visible light; As long as through the lens of the ultraviolet light is lower than 2%, even if qualified. Labeled 'UV', 'anti ultraviolet' : said the lens to block below 380 nm UV; As long as through the lens of the ultraviolet light is lower than 2%, even if qualified. ; Labeled '100% UV absorption' : it means the function of the lens is 100% for UV absorption; But through the lens of the ultraviolet light is lower than 0. 5%, even if qualified.