Comprehensive Knowledge of Glasses Manufacturing and Glasses [Part 4]
...... About glasses lenses . After talking about the frames, it's time to talk about glasses lenses. Lenses are the most important part of the frames, and can be said to be the soul of glasses. Why say soul, because lenses are functional. Imagine if the frames were not invented, would you still have a pair of glasses if you used a pair of lenses with a rubber band and a stick? Lenses are important, I won't say much, and if you don't even understand the importance of lenses, it's useless to say more. Main materials and characteristics of lenses. 1. Resin lenses. Lightweight (density about 1.32), impact-resistant, and affordable. The disadvantages are easy to scratch (need coating), low refractive index (1.50-1.74), suitable for ordinary degrees and daily wearers. 2. Glass lenses, high light transmittance (99%), high refractive index (up to 1.9), disadvantages are relatively heavy (density 2.54), fragile, poor safety, suitable for ultra-high degrees (need ultra-thin)...