Glasses lens knowledge 59. Fake Ray Ban Sunglasses Sale what kind of lens material? Natural material Branch: crystal stone, high hardness, easy to grind, through the ultraviolet, birefringence. Artificial materials: including Cheap Replica Ray bans UK inorganic glass, plexiglass and optical resin. ① inorganic glass: by the silica, calcium, aluminum, sodium, potassium and other smelting, transparency is good. ② plexiglass: chemical composition of polymethyl methacrylate. ③ optical resin: chemical composition is propylene diethylene glycol carbonate. The advantage is that light weight, impact resistance, casting molding, easy to dye. 60, Cheap Ray Bans the advantages and disadvantages of resin lenses? Advantages: light weight, not fragile, broken and no edges and corners, security Disadvantages: not wear-resistant lens thicker price slightly higher 61, the advantages and disadvantages of glass lenses? Advantages: wear-resistant lenses thin optical properties of low price Disadvantages: heavy fragile unsafe 62, resin and glass than the difference between the two? Selection process is not the same, the resin is a special material - made of polycarbonate, Material cost is not the same, so the price of resin lenses a little higher. The difference between the two is that the resin lens technology is higher than the glass, the resin is light, not fragile, blocking the ultraviolet light, the light is good, easy to dye, the glass is safe and beautiful; the glass lens is heavy, fragile, thinner than the resin sheet The Resin sheet without glass plate hardness is high, easy to scratch. Both have their own characteristics, have their own strengths. Children, adolescents recommend with resin tablets.

63, the lens safety center thickness (international)? Resin 1.0MM glass 0.7MM 64, Abbe number with the dispersion, the relationship between the refractive index? Abbe number with the dispersion is inversely proportional relationship is usually Abbe number with the refractive index is also inverse relationship 65, Wholesale Ray Bans resin lens which refractive index? 1.499 1.56 1.61 1.67 1.701 1.74 66, what kind of lens should I choose for different refractive index lenses? 500 degrees or less 1.56 / 1.61,500-800 degrees recommended 1.61-1.67,800 degrees above recommended 1.67-1.74. 67, what is the optical center? The light passes through the lens without changing its own direction. 68, what is the dual light lens? The same lens has two luminosity, glazing for the far area, the light for the near area. 69, multifocal lens What are the characteristics? A pair of glasses to see the distance in the distance, seamless, beautiful, for young people to control myopia, middle-aged presbyopia patients can make life more convenient. 70, what is hard lenses? Plus hard, as the name implies, is the lens is harder than ordinary lenses, plus hard film with a super wear-resistant characteristics, the principle is the surface of the lens coated with special ultra-fine particles plus hardening, enhanced lens wear resistance, extend the service life
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